PASPC Convective Outlook Day 1

FOCN45 CWWG 221200

SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT THURSDAY JUNE 22 2017.

ALERTS IN EFFECT... NONE AT THIS TIME.

SYNOPTIC OVERVIEW... UPPER LOW SPINNING OVER CENTRAL MANITOBA WITH 994 MB SFC REFLECTION NEAR THE PAS. ANOTHER UPPER LOW IS OVER FOXE BASIN WITH TROUGH SOUTHWESTWARD TO ANOTHER UPPER LOW NORTHWEST OF STONY RAPIDS. UPPER RIDGE OVER WESTERN ARCTIC, BUT THERE IS AN UPPER TROUGH MAKING ITS WAY EASTWARD TOWARDS BANKS ISLAND.

DISCUSSION...

ALBERTA... THE RAIN THAT MOVED THROUGH CENTRAL ALBERTA OVERNIGHT WILL EXIT SOUTHEASTERN PARTS OF THE PROVINCE THIS AFTERNOON. ONLY ABOUT 5 MM OF RAIN IS EXPECTED WITH THIS BAND OF PRECIPITATION. HOWEVER, WITH LOW FREEZING LEVELS LIGHT SNOW IS POSSIBLE IN THE MOUNTAINS. A SURFACE RIDGE BEGINS TO MOVE IN FROM THE WEST LATER TODAY, CAUSING SURFACE WINDS THROUGHOUT MOST OF THE PROVINCE TO REMAIN IN THE 30 GUSTING 50 KM/H RANGE. WITH COLDER AIR IN THE LOWER LEVELS SOME INSTABILITY REMAINS THROUGHOUT MUCH OF THE PROVINCE, BUT WITH UPSLOPE FLOW EXPECTED ALONG THE FOOTHILLS THIS AFTERNOON, THIS INSTABILITY WILL BE ENHANCED. ONLY 100-250 J/KG OF MLCAPE IS EXPECTED SO IF THUNDERSTORMS DO FORM ALONG THE FOOTHILLS THEY WILL BE WEAK. THE NORTHWEST FLOW ALOFT WILL CARRY ANY SHOWERS/THUNDERSTORMS THAT DO DEVELOP THIS AFTERNOON SOUTHWARDS ALONG THE FOOTHILLS AND COULD LAST INTO THE OVERNIGHT HOURS.

ON FRIDAY A MORE DEFINED AREA OF INSTABILITY WILL LIKELY PRODUCE SHOWERS OR THUNDERSTORMS ANYWHERE FROM HIGH LEVEL TO THE CAPITAL REGION.

EASTERN PRAIRIES... SHOWERS OVER MOST OF MANITOBA TODAY AND INTO TONIGHT AS THE LOW NEAR THE PAS SPINS ROUND AND ROUND. WHEN THIS LOW STARTS TO LEAVE THE PROVINCE OVERNIGHT, THE UPPER LOW NORTHWEST OF STONY RAPIDS DIPS SOUTH TO BRING MORE SHOWERS TO THE PROVINCE. WITH ALL THE SPIN OVER THE PROVINCE TODAY THERE IS A CHANCE FUNNEL CLOUDS COULD FORM AS THE SHOWERS DEVELOP. ALTHOUGH A RISK OF AN ISOLATED THUNDERSTORM WILL EXIST OVER NORTH AND CENTRAL REGIONS, THERE IS NOT MUCH INSTABILITY, SO NOT EXPECTING MUCH MORE THAN SOME GUSTY WINDS AND BRIEF DOWNPOURS FROM ANY THAT DO FORM. WINDS ON THE BACKSIDE OF THIS LOW WILL BE A CONCERN TODAY. THE PARKLANDS OF MANITOBA COULD SEE SOME STRONG GUSTS THIS MORNING UP TO 80 KM/H FROM THE WEST. SOUTHERN SASKATCHEWAN COULD ALSO EXPERIENCE STRONG WINDS FROM THE NORTH LATER TODAY. SHOWERS FOR SOUTHERN SASKATCHEWAN TODAY AS THE TROUGH CURRENTLY OVER CENTRAL REGIONS CONTINUES TO TRACK SOUTHWARD. 5-10 MM OF RAIN IS FORECAST FOR NORTHEASTERN SASKATCHEWAN TODAY.

EASTERN ARCTIC... SLOW MOVING LOW WILL CONTINUE TO GIVE LIGHT MIXED PRECIPITATION TO THE MELVILLE PENINSULA TODAY AND TONIGHT WITH FOG AT TIMES. SHOWERS OVER ARVIAT TODAY AHEAD OF THE UPPER TROUGH, WITH 5-10 MM IN THE FORECAST.

WESTERN ARCTIC... SHOWERS AND NON-SEVERE THUNDERSTORMS FORECAST IN WESTERN AND SOUTHWESTERN REGIONS OF THE MACKENZIE TODAY.

END/SHAER/VALLEE