PASPC Convective Outlook Day 1

FOCN45 CWWG 221900

SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM 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 THIS MORNING WILL EXIT SOUTHEASTERN PARTS OF THE PROVINCE THIS AFTERNOON. 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. SLIGHT UPSLOPE FLOW EXPECTED ALONG THE FOOTHILLS THIS AFTERNOON. 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.

WITH THE COLD AIRMASS A FEW SITES ALONG THE FOOTHILLS HAD FROST THIS MORNING INCLUDING BLACK DIAMOND AT -1.4, NIER AT -0.1, AND A FEW SITES IN THE CARDSTON REGION CAME CLOSE. CENTRAL ALBERTA HAS A RISK TONIGHT AS LOWS WILL BE NEAR 3 DEGREES. LOW LYING AREAS OR THE FOOTHILLS COULD GET CLOSE IN A FEW LOCALITIES.

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

EASTERN PRAIRIES...COLD LOW SHOWERS THROUGHOUT CENTRAL SK/MB DIVING SOUTHWARD. COLD AIRMASS THUNDERSTORMS IN DRYSLOT WRAPPING IN FROM ONTARIO INTO NORTHERN MANITOBA, AND THEN AROUND INTO THE MB INTERLAKE. HARD SHOWERS, COLD CORE FUNNELS, MAYBE SOME SMALL GRAUPLE. SOUTH OF THE ADVANCING COLD LOW (SOUTHERNMOST SK AND TO A LESSER EXTENT SOUTHERN MB) WESTERLY GRADIENT, DRY INSTABILITY, AND A BIT OF IPV BRINGING GUSTS 70 TO 80 KM/H. SOME INSTABILITY IN THIS AIRMASS BUT DRY, STRONG WINDS WILL OVERPOWER ANY FLEDGLING CONVECTION.

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

END/BAGGALEY/WIELKI