104 FXUS63 KBIS 220553 AFDBIS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BISMARCK ND 1253 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 1253 AM CDT MON JUL 22 2013 NO SIGNIFICANT CHANGES REQUIRED WITH THIS FORECAST UPDATE OTHER THAN TO BLEND TO THE OBSERVED TRENDS THROUGH 05 UTC. DID MAINTAIN ISOLATED POPS THROUGH 08 UTC ACROSS THE JAMES RIVER VALLEY GIVEN THE LATEST RADAR TRENDS. UPDATE ISSUED AT 953 PM CDT SUN JUL 21 2013 UPDATE TO REMOVE ALL COUNTIES FROM THE TORNADO WATCH AND COMPLETELY CANCEL THE WATCH. UPDATES FORTHCOMING. EXPECT THE REST OF THE NIGHT TO DRY OUT WITH TRANQUIL WEATHER COMMENCING. UPDATE ISSUED AT 827 PM CDT SUN JUL 21 2013 UPDATE TO REMOVE MOST OF OUR NORTH CENTRAL AND SOUTH CENTRAL COUNTIES. PORTIONS OF OUR EAST CENTRAL ZONES REMAIN IN A TORNADO WATCH UNTIL 10 PM CDT. UPDATE ISSUED AT 714 PM CDT SUN JUL 21 2013 UPDATED THE FORECAST TO EXPAND THE TORNADO WATCH SOUTHEAST TO INCLUDE THE JAMES RIVER BASIN. ALSO UPDATED THE FORECAST TO REMOVE THE WATCH FROM THE WESTERN COUNTIES. ALSO ADJUSTED HOURLY POPS BASED ON CURRENT RADAR OBS AND TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 431 PM CDT SUN JUL 21 2013 THIS UPDATE TO ADD SOUTH CENTRAL ND INCLUDING BURLEIGH...MORTON AND KIDDER COUNTIES TO WATCH. UPDATE ISSUED AT 416 PM CDT SUN JUL 21 2013 THIS UPDATE TO CLEAR TORNADO WATCH FROM FAR NORTHWEST ND. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 245 PM CDT SUN JUL 21 2013 MAIN CONCERNS THIS SHORT TERM PERIOD WILL BE SEVERE STORMS. LATEST SATELLITE LOOPS SHOW SHORTWAVE TROUGH MOVING THROUGH SASKATCHEWAN INTO EASTERN MONTANA. A SURFACE TROUGH ASSOCIATED WITH THE SHORTWAVE WAS ACTIVELY SUPPORTING A LINE OF THUNDERSTORMS. EXPECT LINE OF THUNDERSTORMS DEVELOPING BETWEEN WILLISTON AND ESTEVAN SASK...MOVING EAST WITH TIME ACROSS THE NORTH CENTRAL. LESS ACTIVE THUNDERSTORM CHANCES SOUTH CENTRAL...BUT THREAT STILL EXISTS THIS EVENING. LINE OF THUNDERSTORMS/MCS WILL EXIT THE REGION LATE TONIGHT. HIGH PRESSURE WILL FOLLOW WITH COOLER AND DRY WEATHER MONDAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 245 PM CDT SUN JUL 21 2013 THE MAIN CONCERN IN THE LONG TERM WILL BE THE CHANCES OF THUNDERSTORMS. MUCH OF THE LONG TERM FORECAST PERIOD WILL FEATURE A H5 RIDGE ACROSS THE WESTERN UNITED STATES WITH A TROUGH IN THE EAST. THIS WILL PLACE THE NORTHERN PLAINS IN NORTHWESTERLY FLOW ALOFT...WITH PERIODIC SHORTWAVES MOVING ACROSS NORTH DAKOTA. A SURFACE BOUNDARY IS EXPECTED TO BE LOCATED FROM NORTH CENTRAL MONTANA INTO EASTERN WYOMING MONDAY AFTERNOON. THIS COULD PROVIDE THE FOCUS FOR THUNDERSTORMS MONDAY NIGHT...ESPECIALLY ACROSS WESTERN NORTH DAKOTA. SURFACE HIGH PRESSURE BUILDS INTO NORTH DAKOTA ON TUESDAY...BUT QUICKLY SHIFTS EAST TUESDAY NIGHT. THERE IS RELATIVE AGREEMENT AMONGST THE SHORT TERM MODELS THAT THUNDERSTORM CHANCES WILL RETURN TUESDAY NIGHT THOUGH THE PLACEMENT OF THE HIGHER CHANCES IS NOT AS CLEAR. THE GFS AND ECMWF FAVOR THE NORTH AND EAST PARTS OF THE FORECAST AREA...AND THIS IS ALSO IN LINE WITH THE CURRENT FORECAST. A STRONGER WAVE MOVES ACROSS LATE IN THE WEEK...TOWARDS THURSDAY AND FRIDAY. IT ALSO APPEARS A WARM FRONT SETS UP ACROSS SOUTHERN NORTH DAKOTA THURSDAY NIGHT INTO FRIDAY...WHICH SHOULD SHOULD BRING A MORE ORGANIZED CHANCE OF THUNDERSTORMS LATE IN THE WEEK. THE GFS AND ECMWF DIVERGE A BIT TOWARDS THE WEEKEND...THOUGH THE GENERAL IDEA IS THE H5 RIDGE BUILDS ACROSS NORTH DAKOTA WITH SURFACE HIGH PRESSURE TALKING HOLD ON SATURDAY. THIS SHOULD HELP DRY IT OUT TO SOME EXTENT ON SATURDAY AND WILL STICK WITH SPOTTY SLIGHT CHANCE POPS. ANOTHER BOUNDARY BECOMES ESTABLISHED ACROSS PARTS OF MONTANA INTO CENTRAL WYOMING FOR SUNDAY WITH THUNDERSTORM CHANCES POTENTIALLY INCREASING AGAIN IN THE WEST JUST BEYOND LONG TERM FORECAST PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1253 AM CDT MON JUL 22 2013 MVFR STRATUS ACROSS SOUTHEAST SASKATCHEWAN IS EXPECTED TO CONTINUE TO BUILD DOWN INTO NORTH DAKOTA...AND IMPACT KMOT AFTER 08 UTC. SOME UNCERTAINTY REMAINS AS TO IF THIS STRATUS WILL BE ABLE TO BUILD INTO KISN...AND THUS...LEFT IT OUT AT THIS TIME. DID ADD A TEMPO GROUP FOR FOG AT KBIS TONIGHT GIVEN THE RAINFALL SUNDAY EVENING...AND WILL HAVE TO MONITOR FOR POSSIBLE FOG/STRATUS DEVELOPMENT AT KJMS GIVEN THE LATEST FOG CHANNEL SATELLITE TRENDS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...WAA LONG TERM...CK AVIATION...AYD