914
FOCN45 CWWG 191900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT SUNDAY JULY
19 2026.
ALERTS IN EFFECT...AIR QUALITY WARNINGS FOR THE SOUTHERN NWT AND
PORTIONS OF THE NORTHERN PRAIRIES. HEAT WARNINGS FOR PARTS OF
NORTHERN SASKATCHEWAN, AND PARTS OF SOUTHERN AND CENTRAL MANITOBA.
SEVERE THUNDERSTORM WATCHES FOR PARTS OF NORTHERN SASKATCHEWAN AND
MANITOBA.
OVERVIEW...ALOFT, AN UPPER LOW SITS OVER THE CENTRAL AB/SK BORDER
WITH AN ASSOCIATED TROUGH EXTENDING NORTHEAST THROUGH MAINLAND
NUNAVUT TO FOXE BASIN. AN UPPER RIDGE EXTENDS FROM THE CENTRAL CONUS
NORTHWARDS POKING INTO THE EASTERN PRAIRIES. DOUBLE BARREL LOW
COMPLEX WITH LOWS OVER THE GASPE PENINSULA AND UNGAVA BAY WITH AN
ASSOCIATED TROUGH EXTENDING NORTHWESTWARD THROUGH BAFFIN ISLAND.
AT THE SURFACE, THERE IS A 1001 MB LOW IN CENTRAL SASKATCHEWAN. A
WARM FRONT FROM THIS LOW BISECTS MANITOBA, AND A COLD FRONT EXTENDS
SOUTHWARD THROUGH SOUTHWESTERN SASKATCHEWAN. A WEAKENING 1002 MB LOW
SITS IN HUDSON STRAIT. A SECOND WEAKER FRONTAL WAVE FROM AN APEX
BETWEEN YBK AND YCS WITH COLD FRONT EXTENDING WEST AND NORTH AND WARM
FRONT TO THE SOUTH.
DISCUSSION...
AB...WILDFIRE SMOKE IS DRIFTING INTO NORTHERN ALBERTA FROM THE NWT,
AND AIR QUALITY WARNINGS CONTINUE. IN THE NORTHERLY FLOW BEHIND THE
SASKATCHEWAN LOW, SMOKE WILL DRIFT SOUTHWARD INTO CENTRAL AND
SOUTHERN ALBERTA.
NORTHERN AND CENTRAL REGIONS WILL SEE SHOWERS AND THUNDERSTORMS TODAY
AND TONIGHT. A LACK OF SHEAR MEANS THAT THUNDERSTORMS WILL GENERALLY
BE NON-SEVERE IN NATURE. THERE EXISTS POTENTIAL FOR FUNNEL CLOUDS
UNDERNEATH THE UPPER LOW. A SHORT-WAVE RIDING THE NORTHERLY FLOW
COULD BRING 20 TO 30 MM OF RAIN TO WEST-CENTRAL ALBERTA TONIGHT.
SK/MB...
THE PATTERN AND FOCUS FOR MAJOR CONVECTION IS OVER MANITOBA TODAY AS
THE LOW CENTER SITS NEAR FLIN FLON BY MIDDAY. WITH THE WARM FRONT
RUNNING EAST AND THE COLD FRONT SOUTHWARDS ALONG THE SK/MB BORDER IN
THE AFTERNOON, MOST OF SOUTHERN AND CENTRAL MB WILL BE SITTING IN
20C+ DEWPOINTS AND SIGNIFICANT INSTABILITY FOR THE DAY; 1500 TO 2500
J/KG MLCAPE ALONG WITH 40 KNOTS OF DEEP SHEAR BELOW A 100 KNOT UPPER
LEVEL DIFFLUENT CYCLONIC JET WITH LEFT EXIT SITUATED PERFECTLY IN
LOCATION AND TIMING.
THERE ARE, IN SPOTS, SOME NICELY VEERING PROFILES TO SUPPORT
SUPERCELLS AND ALL WEATHER HAZARDS: HEAVY RAIN, LARGE HAIL, DAMAGING
WINDS, AND TORNADOES. THERE WILL BE THUNDERSTORMS AND SEVERE
THUNDERSTORMS FOR THE AREA, AND A BROAD HIGH RISK FOR MUCH OF IT.
BUT THE OVERALL CHARACTER OF THE DAY SO FAR IS STILL ONE OF
CONDITIONS AND UNCERTAINTY FOR MODE AND TIMING. THERE IS A STRONG CAP
FORECAST OVER THE ENTIRE AREA, CONFIRMED BY THE 15Z SOUNDING FROM
YWG, EXPECTED THROUGH THE AFTERNOON AND EVENING, ALTHOUGH AN UPCOMING
19Z SOUNDING AT YWG WILL HELP FOR CONFIRMATION. WITH THAT, ISOLATED
CELLS OR SUPERCELLS AHEAD OF THE COLD FRONT, ALONG THE WARM SECTOR
TROUGH ARE NOT LIKELY, BUT CANNOT BE RULED OUT. LINGERING
THUNDERSTORMS AND ASSOCIATED OUTFLOW BOUNDARIES, COUPLED WITH TERRAIN
AND LAKE BREEZE INTERACTIONS, MAY PROVE ENOUGH TO OVERCOME THE CAP
OUTRIGHT. EVEN IF NOT, ELEVATED CONVECTION ITSELF CAN RESURFACE AS IT
PROGRESSES SOUTHEAST INTO THE AFTERNOON.
CAMS ARE NOT AGREEING ON ANY SOLUTION.
GENERALLY, FORECASTER CONFIDENCE IS HIGHER FOR A SOLUTION OF SEVERE
THUNDERSTORM DEVELOPMENT ALONG THE COLD FRONT RAPIDLY GROWING UPSCALE
INTO BOWING SEGMENTS OVER WESTERN MANITOBA. THESE THUNDERSTORMS WILL
BE DOMINATED BY INCREASINGLY WESTERLY WINDS ALOFT PRODUCING A THREAT
OF VERY HIGH STRAIGHT LINE WINDS AT THE SURFACE - WELL IN EXCESS OF
100 KM/H. THE COMBINATION OF ALL THE ABOVE MAKES TIMING PARTICULARLY
HARD TO NAIL DOWN, WITH MAJOR ACTIVITY IN THE RRV RANGING ANYWHERE
FROM LATE MORNING TO LATE EVENING WHEN THE COLD FRONT IS ABOUT TO
EXIT THE PROVINCE.
AT ANY RATE, EVEN WITH THE CAPPING INVERSION, THERE REMAIN MULTIPLE
OPPORTUNITIES FOR WIDESPREAD AND RAPID THUNDERSTORM DEVELOPMENT.
WHILE THEY DIFFER IN PARTICULARS, NEARLY ALL ARE INDICATING POTENTIAL
FOR ONE OR MORE MAJOR HAZARDS OVER SOUTHERN MANITOBA. SEVERE ACTIVITY
WILL DEPART SOUTHEAST OUT OF THE PROVINCE EARLY OVERNIGHT INTO
MONDAY.
WILDFIRES CONTINUE TO BURN IN NORTHERN MB AND SK, REDUCING AIR
QUALITY DOWNWIND OF THE FIRES. AIR QUALITY WARNINGS CONTINUE FOR THE
AREA. SMOKE IS EXPECTED TO SPREAD SOUTH BEHIND THE COLD FRONT INTO
SOUTHERN SASKATCHEWAN TOMORROW. HOW MUCH SURFACES TO REDUCE AQHI
VALUES IS TO BE SEEN.
UNDER THE INFLUENCE OF THE UPPER RIDGE PARTS OF NORTHERN
SASKATCHEWAN, AS WELL AS SOUTHERN AND CENTRAL MANITOBA WILL SEE HEAT
WARNING CRITERIA BEING MET. DAYTIME HIGHS IN THE LOW 30S COMBINED
WITH OVERNIGHT LOWS IN THE HIGH TEENS AND HUMIDEX VALUES 38 AND
HIGHER WILL CONTINUE THROUGH THE WEEKEND.
THUNDERSTORM RISK FOR THE EASTERN PRAIRIES ON DAY 2 REMAINS MARGINAL.
IN THE NORTHWEST UNIDIRECTIONAL FLOW, 0-6 KM SHEAR OF 25 KT AND
SBCAPE NEAR 1000 J/KG, A SURFACE TROUGH FROM THE LOW IN NW ONTARIO IS
EXPECTED TO BE THE FOCUS FOR DEVELOPMENT. A SEVERE TS IS NOT OUT OF
THE QUESTION, BUT AT THIS POINT A SEVERE AREA ON THE OUTLOOK IS NOT
WARRENTED.
NT/NU...A LOT OF WILDFIRE SMOKE CONTINUES TO CIRCULATE AROUND THE
SOUTHERN NORTHWEST TERRITORIES. AIR QUALITY WARNINGS REMAIN. IN
NORTHERN REGIONS, DAYTIME HIGHS IN THE HIGH 20S ARE EXPECTED TO
RETURN EARLY THIS WEEK.
AS THE LABRADOR LOW CONTINUES TO SPIN, SOUTHEASTERN BAFFIN ISLAND
WILL SEE SHOWERS CONTINUE OVER THE NEXT FEW DAYS WITH NO SIGNIFICANT
QPF IN ANY TOWN SITES.
END/SPC-WPG/VALLEE
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