475 FXUS65 KTFX 031733 AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1130 AM MDT SUN APR 3 2016 AVIATION SECTION UPDATED .UPDATE... QUIET WEATHER CONDITIONS ACROSS CENTRAL/SOUTHWEST MT THIS MORNING, WITH JUST A FEW AREAS OF PARTLY/MOSTLY CLOUDY SKIES FROM CUT BANK TO LEWISTOWN AS POCKETS OF MID-LEVEL MOISTURE MOVE DOWN THE EAST SIDE OF THE HIGH PRESSURE RIDGE OVER WA/OR. WATER VAPOR SATELLITE IMAGERY SHOWS SOME ADDITIONAL MOISTURE WEST OF THE CONTINENTAL DIVIDE THAT WILL ARRIVE THIS AFTN, GENERATING A FEW ISOLATED SHOWERS FOR THE HILINE AND CENTRAL COUNTIES. SCATTERED SHOWERS AND POSSIBLY A FEW WEAK, SHORT-LIVED THUNDERSTORMS (NAM MODEL INDICATING CAPE VALUES OF 200-400 J/KG AND LIFTED INDICES TO -2) ARE EXPECTED OVER THE SOUTHWEST MTN RANGES, ALONG WITH THE BRIDGERS/LITTLE BELTS/JUDITH/SNOWY MOUNTAINS. JUST MINOR FORECAST ADJUSTMENTS THIS MORNING, NAMELY FOR CLOUD COVER AND AFTN DEWPOINT TEMPS/HUMIDITY, AND TO INCLUDE THE MENTION OF THUNDERSTORMS. WARANAUSKAS && .AVIATION... UPDATED 1730Z. VFR CONDITIONS EXPECTED THROUGH TONIGHT. POCKETS OF MOISTURE MOVING THROUGH NORTHWEST FLOW ALOFT WILL PRODUCE AREAS OF SCT-BKN MID-LEVEL CLOUDS ACROSS CENTRAL/SOUTHWEST MT THROUGH EARLY EVENING. SOME OF THE MOISTURE MAY GENERATE A FEW ISOLATED SHOWERS AROUND KGTF/KHLN/ KLWT/KBZN, BUT SPARSE COVERAGE MAKES CONFIDENCE TOO LOW TO MENTION IN 18Z TAFS. ALSO, MARGINAL INSTABILITY AND OROGRAPHIC LIFT MAY PRODUCE A FEW SMALL, SHORT-LIVED THUNDERSTORMS OVER THE CENTRAL AND SOUTHWEST MTN RANGES THIS AFTN. ALL THE CONVECTIVE ACTIVITY SHOULD DISSIPATE 00-02Z, WITH MIX OF CLEAR SKIES AND MID-LEVEL CLOUDS EXPECTED OVERNIGHT. WARANAUSKAS && .PREV DISCUSSION... /ISSUED 538 AM MDT SUN APR 3 2016/ TODAY THROUGH TUESDAY...UPPER RIDGE OVER INTERMOUNTAIN REGION THIS MORNING WILL MOVE INTO WESTERN MONTANA THIS EVENING. NORTHWEST FLOW AND ENOUGH MOISTURE THIS AFTERNOON TO PRODUCE SCATTERED MOUNTAIN SHOWERS. TEMPERATURES WILL BE SLIGHTLY COOLER TODAY BUT STILL WELL ABOVE NORMAL. AN UPPER LEVEL PACIFIC LOW PUSHES INTO WESTERN MONTANA LATE MONDAY AFTERNOON THEN SWEEPS ACROSS THE STATE AND INTO NORTH DAKOTA BY TUESDAY AFTERNOON. A FAIR AMOUNT OF MOISTURE ACCOMPANIES THIS LOW PRESSURE SYSTEM AND WILL PRODUCE WIDESPREAD SCATTERED SHOWERS MONDAY NIGHT AND TUESDAY. ISOLATED THUNDERSTORMS ARE EVEN POSSIBLE OVER SOUTHWEST AND CENTRAL MOUNTAINS MONDAY AFTERNOON. AS THE LOW PRESSURE SYSTEM MOVES EAST OF THE CONTINENTAL DIVIDE...WINDS WILL BECOME GUSTY AND SPREAD EASTWARD ACROSS THE PLAINS MONDAY NIGHT AND INTO TUESDAY. TEMPERATURES ON MONDAY REMAIN ABOVE NORMAL...BUT ON TUESDAY WILL BE CLOSER TO SEASONAL NORMALS. TUESDAY NIGHT THROUGH SUNDAY...WINDY CONDITIONS AND A FEW SHOWERS WILL LINGER INTO TUESDAY EVENING BUT UPPER LEVEL RIDGING IS STILL EXPECTED FROM MID TO LATE WEEK. THIS WILL BRING MOSTLY CLEAR TO PARTLY CLOUDY SKIES AND WARM TEMPERATURES. BREEZY TO WINDY CONDITIONS PERSIST THROUGH WEDNESDAY EVENING BUT TOWARD THE END OF THE WEEK AM EXPECTING WINDS TO DIMINISH. MODELS CONTINUE TO SHOW SIGNIFICANT DIFFERENCES FOR NEXT WEEKEND WITH THE ECMWF REMAINING THE COOLER AND WETTER MODEL COMPARED TO THE GFS. HAVE KEPT THE FORECAST LEANING TOWARD THE ECMWF SOLUTION WHICH WILL BRING IN ISOLATED/SCATTERED SHOWERS THROUGH THE WEEKEND PERIOD WITH TEMPERATURES COOLING BACK TOWARD SEASONAL AVERAGES EACH DAY. MPJ && .PRELIMINARY POINT TEMPS/POPS... GTF 65 41 65 36 / 20 10 30 30 CTB 62 38 60 35 / 20 10 20 20 HLN 67 39 63 35 / 10 0 50 40 BZN 67 35 65 30 / 10 10 40 60 WEY 51 34 50 26 / 30 30 50 60 DLN 65 37 60 29 / 20 10 40 50 HVR 64 35 72 36 / 10 10 20 40 LWT 63 37 70 33 / 20 10 30 50 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ WEATHER.GOV/GREATFALLS