922
FOCN45 CWWG 191200
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM 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 EAST-CENTRAL SASKATCHEWAN
AND WEST-CENTRAL MANITOBA.
OVERVIEW...ALOFT, AN UPPER LOW SITS OVER THE CENTRAL AB/SK BORDER.
AN UPPER RIDGE EXTENDS FROM THE CENTRAL CONUS NORTHWARDS POKING INTO
THE SOUTHEAST PRAIRIES. AN UPPER LOW AND TROUGH WEST-EAST THROUGH
MAINLAND NUNAVUT AND A LONGWAVE TROUGH EXTENDING FROM SOUTHERN BAFFIN
ISLAND SOUTHWARD THROUGH QUEBEC AND INTO THE NORTHEAST US.
AT THE SURFACE, THERE IS A 1000 MB LOW IN WESTERN SASKATCHEWAN.
A WARM FRONT FROM THIS LOW SLUMPS SOUTHEASTWARD INTO SOUTHERN
MANITOBA, AND A COLD FRONT EXTENDS SOUTHWARD THROUGH WESTERN
SASKATCHEWAN. A WEAKENING LOW SITS SOUTHEAST OF BAFFIN ISLAND, AND A
990 MB LOW SITS OVER NEW BRUNSWICK.
DISCUSSION...
AB...SMOKE HAS DRIFTED INTO NORTHERN ALBERTA FROM THE NWT, AND AIR
QUALITY WARNINGS CONTINUE. IN NORTHWEST FLOW BEHIND LAST NIGHT'S
SYSTEM, SMOKE WILL STREAM SOUTHWARD INTO SOUTHERN AND CENTRAL ALBERTA
BEGINNING TODAY.
WHAT'S LEFT OF THIS SYSTEM IS LIKELY TO BRING WIDESPREAD SHOWERS AND
TS THIS AFTERNOON AND EVENING. PRECIP WRAPPING AROUND IT IS LIKELY TO
BRING 20-30 MM RAIN TO PARTS OF WEST-CENTRAL ALBERTA.
THUNDERSTORMS ARE ALSO LIKELY TODAY BUT THEY WILL BE OF THE
NON-SEVERE VARIETY. THERE ALSO EXISTS POTENTIAL FOR FUNNEL CLOUDS
DIRECTLY UNDERNEATH THE VERTICALLY STACKED UPPER LOW.
SK/MB...SOME THUNDERSTORMS NORTH OF THE WARM FRONT LINGER THIS
MORNING IN AREAS OF EAST-CENTRAL SASKATCHEWAN AND WEST-CENTRAL
MANITOBA AS THE LLJ RAMPED UP OVERNIGHT. THESE STORMS ARE EXPECTED TO
CONTINUE TO PUSH EASTWARD THROUGH THE MORNING HOURS.
THE PATTERN AND FOCUS FOR MAJOR CONVECTION SHIFTS EAST TO MANITOBA
TODAY AS THE LOW CENTER SITS NEAR FLIN FLON BY MIDDAY. WITH THE WARM
FRONT RUNNING EAST FROM THAT POINT 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 JET. 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 ROUGHLY -30
J/KG OR STRONGER MLCIN FORECAST OVER THE ENTIRE AREA THROUGH THE
AFTERNOON AND EVENING. WITH THAT, ISOLATED CELLS OR SUPERCELLS IN THE
MAIN AIRMASS ARE NOT LIKELY. ON THE NORTHERN PERIPHERY, SCATTERED
THUNDERSTORMS CONTINUE THIS MORNING IN THE NORTHERN INTERLAKE.
WHILE THIS MAY DIMINISH LATER ACTIVITY OVER THOSE SAME AREAS, THE
OUTFLOW BOUNDARIES, COUPLED WITH TERRAIN AND LAKE BREEZE
INTERACTIONS, MAY PROVE ENOUGH TO OVERCOME THE CAP OUTRIGHT
ELSEWHERE. EVEN IF NOT, ELEVATED CONVECTION ITSELF CAN RESURFACE AS
IT PROGRESSES SOUTHEAST INTO THE AFTERNOON. LATEST CAMS TEND TO LEAN
INCREASINGLY TOWARD THE LATTERMOST OPTION, GENERALLY INTENSIFYING
RAPIDLY OVER WESTERN MANITOBA INTO BOWING SEGMENTS.
THESE THUNDERSTORMS WILL BE DOMINATED BY INCREASINGLY WESTERLY WINDS
ALOFT AND RAPID UPSCALE GROWTH 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.
BUT 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.
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.
NT/NU...FIRES WERE VERY ACTIVE BETWEEN GREAT SLAVE LAKE AND THE
MACKENZIE RIVER THIS WEEK AND A LOT OF SMOKE WAS THROWN INTO THE
ATMOSPHERE. WHILE NORTHWEST FLOW HAS BROUGHT ABOUT SOME IMPROVEMENT
FOR COMMUNITIES ALONG THE MACKENZIE RIVER, SMOKE WILL CONTINUE SWIRL
AROUND SOUTHERN PORTIONS OF THE TERRITORY, KEEPING AIR QUALITY POOR
IN THE AREA.
DAYTIME HIGHS IN THE LOW 30S MAY RETURN NEXT 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/VAN LOCHEM
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