000 FXUS65 KBYZ 302131 CCA AFDBIL SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BILLINGS MT 157 PM MST SAT MAR 30 2002 .SHORT TERM...VALID FOR SUN...MON...TUE... AVN APPEARS TO BE INITIALIZING BETTER AND HANDLING PRESENT SYSTEM MOVING OVER SC MT...SYSTEM EXITS THE REGION TONIGHT. ETA IS SIMILAR YET DIFFERENT IN PLACEMENT OF SFC LOW OVER CANADA WHICH WOULD AFFECT TIMING/STRENGTH OF FRONT...THUS MORE CONFIDENCE WITH AVN. AREA OF LOW PRESSURE OVER CANADA WILL DRAG A TROUGH ACROSS MT EASTER DAY WITH WINDS GRADUALLY INCREASING. 1000-500MB THICKNESS VALUES ALSO INCREASE ALLOWING FOR READINGS TO WARM. EXPECT TEMPS TO BE THE WARMEST EASTER DAY WHILE TEMPS WILL COOL IN THE WAKE OF THE TROUGH CROSSING THE REGION BY MID DAY MONDAY. NORTHWEST FLOW DEVELOPS AND READINGS COOL FURTHER TUE AS 1000-500MB THICKNESS VALUES TAKE A DIVE TO AROUND 522DM AND 850MB TEMPS FALL TO -16C 12Z TUE. PRESENT TREND OF TEMPS FALLING INTO THE MID 30S BY TUE GOOD BET. BEST CHANCE OF PRECIP WILL BE WITH THE FRONT AND WILL UP POPS TO LIKELY CAT FOR MON AFTN...WITH CONDITIONS DRYING THERE AFTER ALTHOUGH MID/HIGH CLOUDS WILL LINGER. SPRINGER .LONG TERM...VALID FOR WED...THU...FRI...SAT... MODELS ARE PERSISTENT IN KEEPING A NORTHWEST FLOW OVER THE AREA THROUGH THE BULK OF THE EXTENDED PERIOD. DIFFERENCES AT THE BEGINNING DEAL WITH THE STRENGTH OF THE VORT LOBE ADVANCING THROUGH THIS FLOW. CANADA MODELS SEEM TO BE THE STRONGEST WITH THIS FEATURE. CANADA IS ALSO THE WETTEST AS WELL. FARTHER OUT...MRF FLATTENS THE RIDGE AND BRINGS A FAIRLY STRONG SHORT WAVE THROUGH THE FLOW ON SATURDAY. THE RESPONSE ON THE SURFACE IS THE DEVELOPMENT OF A DEEPENING SURFACE LOW OVER EASTERN MONTANA. CANADA ENSEMBLES THROUGH THAT DAY DO NOT SHOW THIS FEATURE. A COMPARISON OF ENSEMBLE RUNS ON BOTH MRF/AVN AND CANADA SHOW MORE CONSISTENCY WITH THE MRF/AVN. HOWEVER...THE SHORT WAVE ADVANCING THROUGH THE AREA SATURDAY DOES NOT APPEAR TO BE AS STRONG ON THE ENSEMBLE RUN. CONSIDERING THE ABOVE...WILL HAVE SOME LOW POPS TUESDAY NIGHT INTO WEDNESDAY...MAINLY OVER MOUNTAIN AREAS...BUT NOT ENOUGH TO WARRANT A MENTION OF PRECIPITATION IN THE FORECAST. THE NEXT POSSIBILITY FOR PRECIPITATION APPEARS TO BE FRIDAY NIGHT INTO SATURDAY ASSOCIATED WITH THE SHORT WAVE. NOT BEING SURE HOW STRONG THIS FEATURE WILL BE...WILL PUT IN A 20 PERCENT FOR POPS BUT MENTION JUST MOSTLY CLOUDY IN THE FORECAST. THICKNESS PATTERNS POINT TO A WARMING TREND THROUGHOUT THE EXTENDED PERIOD. CANADA MODEL APPEARS TO BE THE WARMEST THAT WAY. WILL FOLLOW THE TREND THAT HAS BEEN MENTIONED IN THE PREVIOUS SET. DUE TO UNCERTAINTIES ON SATURDAY...HOWEVER...WILL MORE OR LESS CONTINUE TEMPERATURES FOR FRIDAY INTO SATURDAY. CLOUD COVER BY ITSELF SHOULD PREVENT MORE WARMING FROM OCCURRING. CHB SUN MON TUE WED THU FRI SAT ----------------------------------------------------------- BIL 030/057 037/045 017/039 015/044 025/052 031/056 034/056 30/B 26/S 30/E 21/E 00/B 11/B 22/E LVM 032/060 036/045 016/037 014/044 023/050 030/054 031/052 30/N 26/S 32/J 32/E 00/B 11/B 22/E HDN 028/060 035/044 016/037 013/046 022/055 029/057 031/057 30/B 26/S 30/E 21/E 00/B 11/B 22/E MLS 025/054 032/040 015/037 013/041 021/049 027/053 030/054 30/B 24/S 20/E 11/E 00/B 11/B 22/E 4BQ 024/051 029/041 017/037 014/042 022/050 028/054 031/055 30/B 24/S 20/E 11/E 00/B 11/B 22/E BHK 023/049 027/037 015/034 012/040 018/047 024/050 027/052 30/B 24/S 20/E 11/E 00/B 11/B 22/E SHR 026/058 032/044 019/038 013/043 021/051 029/056 032/056 30/B 26/S 32/J 22/E 00/B 11/B 22/E .BYZ...NONE.