FOCN45 CWWG 221900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM 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. FOG
ADVISORY FOR RESOLUTE.

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 ACROSS SOUTHERN SK/MB HAS LIFTED. PATCHY 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 CONTINUE TO IMPROVE
TODAY 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 WILL DEVELOP OVER SOUTHERN
SASKATCHEWAN TONIGHT. VERTICAL PROFILES SUGGEST THE ORIGIN OF THE
PRECIPITATION WILL BE QUITE FAR REMOVED FROM THE SURFACE WITH
INVERTED-V PROFILES BELOW. LITTLE TO NO INSTABILITY EXISTS ACROSS
SOUTHERN SASKATCHEWAN TONIGHT. THUS, THE THINKING IS THIS AREA OF
SHOWERS WILL LIKELY REMAIN MOSTLY AS VIRGA WITH LITTLE MEASUREABLE
PRECIPITATION ACROSS SOUTHERN SASKATCHEWAN TONIGHT.

THE ATTENTION FOR A MORE ORGANIZED SEVERE WEATHER THREAT RETURNS TO
SOUTHERN SASKATCHEWAN SUNDAY AFTERNOON/OVERNIGHT INTO MONDAY MORNING.
A VIGOROUS SHORTWAVE TROUGH CURRENTLY SITTING OVER THE PACIFIC
NORTHWEST WILL SLOWLY PUSH EAST INTO SOUTHERN ALBERTA SUNDAY.
TWO JETS WILL SPLIT AROUND THE BASE OF THE TROUGH OVER SOUTHWESTERN
SASKATCHEWAN SUNDAY AFTERNOON CREATING AN AREA OF STRONG DIFFLUENCE
THROUGH MUCH OF SOUTHERN SASKATCHEWAN. INSTABILITY AND MOISTURE WILL
ALSO ADVECT AHEAD OF THE TROUGH TONIGHT AND SUNDAY INTO SOUTHERN
SASKATCHEWAN, FUELING SHOWERS AND THUNDERSTORMS THAT ARE EXPECTED TO
DEVELOP LATER IN THE DAY. A LOW PRESSURE SYSTEM IS FORECAST TO
DEVELOP AND MOVE INTO THE LLOYDMINSTER AREA BY 00 UTC MONDAY WITH A
WARM FRONT DRAPING SOUTHEAST THROUGH SOUTH-CENTRAL SASKATCHEWAN, AND
A COLD FRONT SWEEPING EAST THROUGH SOUTHERN ALBERTA INTO SOUTHWESTERN
SASKATCHEWAN. THIS FRONTAL WAVE, IN ADDITION TO THE STRONG DIFFLUENCE
ALOFT WILL BE THE FOCUS FOR DEVELOPMNENT OF THUNDERSTORMS. AN AXIS OF
1000-2000 J/KG OF MLCAPE WILL RUN THROUGH CENTRAL SASKATCHEWAN AND
WILL COMBINE WITH 30-40 KTS OF 0-6 KM BULK SHEAR, SUPPORTING AN
ORGANIZED SEVERE THREAT ACROSS SOUTHERN SASKATCHEWAN. STORMS ARE
EXPECTED TO REMAIN ISOLATED WITH TRANSIENT SUPERCELL STURCTURES TO
START, BUT AS STORMS PROGRESS INTO THE EVENING HOURS CONVECTIVE
COVERAGE IS EXPECTED TO INCREASE AND ORGANIZE INTO A CONVECTIVE
COMPLEX THAT WILL MOVE ACROSS SOUTHERN SASKATCHEWAN. THE MAIN THREAT
WILL BE STRONG WIND GUSTS WITH 90-100 KM/H POSSIBLE AND 2-4 CM HAIL.

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.

PATCHY FOG WILL CONTINUE IN RESOLUTE AND EASTERN BAFFIN ISLAND
COMMUNITIES.

END/BILOUS/ZIOLKOWSKI/ALBRECHT/PATTEN