FOCN45 CWWG 221200
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT SATURDAY
AUGUST 22 2026.

ALERTS IN EFFECT...AQ WARNINGS FOR PARTS OF THE NWT AND THE
MOUNTAIN PARKS IN ALBERTA. HEAT WARNINGS FOR PARTS OF WESTERN SK.

SYNOPTIC OVERVIEW...ALOFT, A LOW EXISTS OVER YT WITH A TROUGH
EXTENDING SOUTH ALONG THE BC COAST WHICH MEETS ANOTHER LOW OVER
THE EASTERN PACIFIC. AN UPPER RIDGE FROM THE US IS CENTRED OVER AB
AND ARCS NORTH INTO NWT. NORTHWEST FLOW EXISTS OVER THE EASTERN
PRAIRIES. AN UPPER LOW SPINS OVER THE EASTERN KITIKMEOT. ANOTHER LOW
IS OVER NORTHWEST ONTARIO WITH ITS LONGWAVE TROUGH EXTENDING SOUTH
INTO THE US. FINALLY, WEAK RIDGING SPRAWLS ACROSS QUEBEC AND
STRETCHES NORTH OVER BAFFIN ISLAND.

AT THE SURFACE, A LOW SITS OVER YT WITH A TROUGH THAT EXTENDS
SOUTHEAST TO ANOTHER LOW JUST WEST OF GREAT SLAVE LAKE. THIS LOW
HAS A TROUGH DEVELOPING OVER NORTHERN AB. WEAK RIDGING EXISTS OVER
THE REST OF AB AND BC. A HIGH PRESSURE CENTRE IS OVER THE SOUTHERN
SK/MB BORDER; ITS RIDGE EXTENDS NORTH OVER MAINLAND NU AND CONTINUES
TO THE ARCTIC ISLANDS. A LOW OVER JAMES BAY HAS TROUGHS EXTENDING
NORTH AND SOUTH OF IT. A WEAK LOW SPINS OVER SOUTHERN BAFFIN
ISLAND. FINALLY, A HIGH PRESSURE OVER THE MARITIMES HAS A RIDGE
STRETCHING OVER QUEBEC.

DISCUSSION...

AB...AN UPPER RIDGE OVER ALBERTA WILL KEEP CONDITIONS WARM AND
GENERALLY QUIET ACROSS THE PROVINCE TODAY. WILDFIRE SMOKE CONTINUES
TO ADVECT INTO PORTIONS OF WESTERN ALBERTA, PARTICULARLY THE MOUNTAIN
PARKS, WHERE WORSENING AIR QUALITY OVERNIGHT HAS PROMPTED AN AIR
QUALITY WARNING. ADDITIONAL AIR QUALITY WARNINGS MAY BE REQUIRED
ACROSS PARTS OF WESTERN AND SOUTHWESTERN ALBERTA LATER TODAY AS SMOKE
CONTINUES TO SPREAD THROUGH THE AREA.

FOR THUNDERSTORMS TODAY, THE UPPER RIDGE IS EXPECTED TO KEEP MUCH OF
THE PROVINCE CAPPED, LIMITING THUNDERSTORM DEVELOPMENT. ONE EXCEPTION
MAY BE A CORRIDOR EXTENDING FROM NORTHWESTERN ALBERTA SOUTHWARD
TOWARD THE HINTON REGION, WHERE A SURFACE TROUGH STRETCHING SOUTH
FROM A DEVELOPING LOW IN THE NORTHWEST TERRITORIES COULD PROVIDE
ENOUGH CONVERGENCE TO INITIATE ISOLATED THUNDERSTORMS LATE THIS
AFTERNOON AND INTO THE EVENING. SHOULD STORMS DEVELOP, AN ENVIRONMENT
CHARACTERIZED BY MLCAPE APPROACHING 2000 J/KG AND EFFECTIVE SHEAR
CLOSE TO OR EXCEEDING 30 KT COULD SUPPORT ISOLATED SUPERCELLS
CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WIND GUSTS.

ON SUNDAY, AN APPROACHING UPPER TROUGH WILL INCREASE THE POTENTIAL
FOR SEVERE THUNDERSTORMS ACROSS MUCH OF ALBERTA.

MB/SK. PATCHY FOG HAS DEVELOPED UNDER THE SURFACE RIDGE IN PARTS OF
SOUTHERN SK/MB THIS MORNING. IT IS EXPECTED TO LIFT LATER THIS
MORNING. FOG IS EXPECTED TO RETURN TONIGHT IN SOUTHEAST MB AS THE
RIDGE AXIS MOVES EAST.

SOME RESIDUAL SMOKE EXISTS IN SOUTHERN MB THAT WAS BROUGHT VIA THE
COLD FRONT YESTERDAY, FROM THE WILDFIRES IN NWT. PM2.5 VALUES HAVE
ONLY MODERATELY ELEVATED IN THESE AREAS AND WILL IMPROVE LATER THIS
MORNING AS THE SMOKE EXITS THE AREA. SMOKE FROM THE FIRES IN NWT AND
IN SOUTHERN BC WILL CONTINUE TO BE MONITORED BUT SHOULD REMAIN ALOFT
FOR TODAY.

THE UPPER RIDGE OVER AB WILL TRACK EAST TODAY, BRINGING WARM AIR TO
SOUTHWEST SK. A QUICK, MARGINAL HEAT EVENT IS EXPECTED FOR THIS
WEEKEND UNTIL AN UPPER LOW MOVES THROUGH THE AREA SUNDAY NIGHT. HEAT
WARNINGS HAVE BEEN ISSUED FOR THE WEST-CENTRAL AREA OF THE PROVINCE.

THE SURFACE RIDGE WILL INHIBIT ANY CONVECTION FOR THE EASTERN
PRAIRIES TODAY. HOWEVER, AS THE SURFACE TROUGH IN NORTHERN AB SLUMPS
SOUTHEASTWARD, AN AREA OF SHOWERS AND THUNDERSTORMS WILL DEVELOP IN
SOUTHWEST SK SATRUDAY NIGHT AND INTO SUNDAY. THESE THUNDERSTORMS ARE
EXPECTED TO REMAIN SUB-SEVERE UNTIL LATER SUNDAY, WHEN AN UPPER JET
ENTERS THE AREA AND ENERGY BUILDS.

NT...SMOKE CONTINUES AFFECTING SOME LOCATIONS.

THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN PORTIONS OF THE
TERRITORY TODAY, WITH A SLIGHT RISK OF SEVERE STORMS SOUTHWEST OF
GREAT SLAVE LAKE. WHILE CAPPING SHOULD LIMIT CONVECTION THROUGH MUCH
OF THE DAY, AN APPROACHING UPPER TROUGH MAY PROVIDE ENOUGH COOLING
ALOFT TO TRIGGER ISOLATED THUNDERSTORMS LATE THIS AFTERNOON AND
EVENING. IF STORMS DEVELOP, MLCAPE NEAR 1000 J/KG AND EFFECTIVE
SHEAR AROUND 30KT COULD SUPPORT A FEW ORGANIZED STORMS, WITH LARGE
HAIL AND STRONG WIND GUSTS AS THE PRIMARY THREATS. HOWEVER,
CONFIDENCE IN STORM INITIATION IS LOW.

OF MORE INTEREST IS A DEVELOPING LOW PRESSURE SYSTEM EXPECTED TO BE
JUST NORTH OF WRIGLEY THIS AFTERNOON. THE SYSTEM WILL BRING STEADY
RAINFALL TO AREAS NEAR AND WEST OF GREAT BEAR LAKE BEGINNING TONIGHT
AND CONTINUING THROUGH SUNDAY. RAINFALL TOTALS OF 30 TO 50 MM
ARE EXPECTED BY SUNDAY EVENING, WITH HIGHER AMOUNTS POSSIBLE CLOSER
TO THE THE TERRAIN AND WITH EMBEDDED CONVECTION.

NU...THE UPPER LOW OVER THE KITIKMEOT WILL TRACK EAST AND BRING
SHOWERS TO THE KIVALLIQ SATURDAY NIGHT AND SUNDAY. HOWEVER, NO
SIGNIFICANT ACCUMULATIONS ARE EXPECTED IN ANY COMMUNITIES.

FOG AT TIMES FOR EASTERN BAFFIN ISLAND COMMUNITIES WILL CONTINUE.

END/BILOUS/ALBRECHT