FOCN45 CWWG 231900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT SUNDAY AUGUST
23 2026.

ALERTS IN EFFECT...AQ WARNING FOR PARTS OF THE NWT. HEAT WARNING FOR
PARTS OF WESTERN SK. FOG ADVISORY FOR THE HIGH ARCTIC. HEAT WARNING
FOR PART OF WESTERN SASKATCHEWAN. SEVERE THUNDERSTORM WATCHES FOR
PARTS OF SOUTHERN SASKATCHEWAN.

SYNOPTIC OVERVIEW...ALOFT, A LOW EXISTS NEAR GREAT BEAR LAKE WITH
ANOTHER CUTOFF UPPER LOW IN SOUTHERN BC. AN UPPER RIDGE FROM THE US
ARCS OVER THE PRAIRIES AND SPRAWLS NORTH OVER CENTRAL ARCTIC.
OTHER UPPER LOWS IN GULF OF ALASKA, OVER EASTERN KITIKMEOT AND OVER
THE GREAT LAKES.

AT THE SURFACE, 998 MB LOW NEAR GREAT BEAR LAKE WITH A TROUGH
SOUTHWARDS ACROSS ALBERTA TO DEVELOPING LOW NEAR SASKATCHEWAN BORDER.
WARM FRONT EAST AND THEN DRAPED ACROSS 60TH PARALLEL ANC COLD FRONT
SOUTHWESTWARDS ACROSS NORHTERN ALBERTA. HIGH PRESSURE CENTRE OVER NW
ONTARIO WITH RIDING NORTHWARDS TO CENTRAL AND HIGH ARCTIC. WEAK LOW
IN FOXE BASIN.

DISCUSSION...

AB/NRN SK...TROUGH OVER ALBERTA WILL DEVELOP A MESS OF THUNDERSTORM
ACTIVITY TODAY. MLCAPE VALUES IN EASTERN ALBERTA ARE FORECAST TO BE
OVER 3000 J/KG BUT THE EBWD IS ONLY AROUND 20 KT. LOOKS LIKE
SIGNIFICANT RAIN AND STRONG WINDS WILL BE THE MAIN HAZARD IN STORMS
THAT DEVELOP THROUGH THE DAY THERE. FOR CENTRAL AREAS MORE DISCRETE
THUNDERSTORMS ARE POSSIBLE WITH AROUND 1500 J/KG MLCAPE AND 30 KT
EBWD. LARGE HAIL WILL BE POSSIBLE. THIS TROUGH WILL DEVELOP INTO A
LOW FORECAST TO SIT OVER CENTRAL SK ON MONDAY. RAIN WILL WRAP AROUND
IT WITH SOME STRONGER NW WINDS ON THE BACKSIDE, IN EASTERN AB, WITH
GUSTS OF 70 KM/H. EAST CENTRAL ALBERTA WILL ALSO LIKELY SEE AT LEAST
25-50 MM OF RAIN, WITH MUCH HIGHER AMOUNTS POSSIBLE IN THUNDERSTORMS,
BUT TO THE NORTH OF WHERE THE STRONGEST WINDS ARE EXPECTED. PARTS OF
CENTRAL SK WILL ALSO GET AROUND 25 MM OF RAIN.

THE SMOKE THAT IS STICKING AROUND A FEW REGIONS ACROSS AB SHOULD
CLEAR OUT THROUGH THE DAY.

MB/SRN SK...THE UPPER RIDGE OVER THE PRAIRIES HAS BROUGHT WARM AIR TO
SOUTHWEST SK. A QUICK, MARGINAL HEAT EVENT CONTINUES FOR TODAY.
HEAT WARNINGS CONTINUE FOR PORTIONS OF THE WEST-CENTRAL AREA OF THE
PROVINCE. THE HEAT WILL END TONIGHT WHEN THE UPPER LOW FROM SOUTHERN
BC ENTERS THE AREA.

THE FOCUS FOR CONVECTION TODAY IS WITH THE DEVELOPING LOW PRESSURE
CENTRE NEAR THE ALBERTA AND SASKATCHEWAN BORDER ALONG TROUGH FROM LOW
IN N.W.T., HOWEVER, ONGOING MORNING CONVECTION CONTINUES OVER
SOUTHEAST SASKATCHEWAN WITH THE ODD STORM BEING SEVERE.

THE LOW WILL MOVE INTO WESTERN SK THIS AFTERNOON, TRIGGERING SHOWERS
AND THUNDERSTORMS. ADDITIONALLY, THE UPPER LOW OVER SOUTHERN BC WILL
PUSH EAST INTO SOUTHERN ALBERTA TODAY. TWO JETS WILL SPLIT AROUND THE
BASE OF THE TROUGH OVER SOUTHWESTERN SK THIS AFTERNOON CREATING AN
AREA OF STRONG DIFFLUENCE. INSTABILITY AND MOISTURE HAS ADVECTED INTO
SK, IN THE SOUTHERLY FLOW AHEAD OF THE TROUGH, BRINGING FUEL FOR THE
THUNDERSTORMS. AN AXIS OF 1000-2000 J/KG OF MLCAPE WILL RUN THROUGH
WESTERN SK AND WILL COMBINE WITH 35 KTS OF 0-6 KM BULK SHEAR,
SUPPORTING AN ORGANIZED SEVERE THREAT. STORMS ARE EXPECTED TO REMAIN
ISOLATED WITH TRANSIENT SUPERCELL STURCTURES TO START. AS STORMS
PROGRESS INTO THE EVENING HOURS, CONVECTIVE COVERAGE IS EXPECTED TO
INCREASE AND ORGANIZE INTO A CONVECTIVE COMPLEX THAT WILL MOVE ACROSS
SOUTHERN SK. THE MAIN THREAT WILL BE STRONG WIND GUSTS OF 90-100 KM/H
AND 2-4 CM HAIL.

THUNDERSTORMS ARE EXPECTED TO CONTINUE INTO THE OVERNIGHT HOURS AS
THE SURFACE TROUGH MOVES INTO EASTERN SK, ALONG WITH THE UPPER
SUPPORT OF THE STRONG DIFFLUENCE. THUNDERSTORMS WILL THEN ENTER INTO
WESTERN MB BY THE MORNING HOURS. THESE THUNDERSTORMS WILL CONTINUE TO
POSE A SEVERE THREAT WITH WIND BEING THE MAIN THREAT OVERNIGHT AND
INTO THE MORNING.

SMOKE FROM THE WILDFIRES IN BC IS EXPECTED TO MOVE BEHIND THE SURFACE
TROUGH AND IS PROGGED TO ENTER WESTERN SK THIS EVENING. PM2.5 VALUES
WILL LIKELY SPIKE BUT WILL BE MONITORED AS THE SMOKE MAKES IT WAY
THROUGH AB TODAY. AIR QUALITY WARNINGS WILL BE ISSUED, IF NECESSARY.

NT...THE GREAT BEAR LAKE LOW WILL SLOWLY WEAKEN AND MOVE EAST THROUGH
MONDAY. 20-30 MM OF RAIN HAS FALLEN AROUND IT SO FAR WITH ANOTHER
10-15 MM EXPECTED LATER TODAY. NON-SEVERE THUNDERSTORMS WILL MOVE
ACROSS THE EASTERN PART OF THE TERRITORY THROUGH TONIGHT.

SMOKE CONTINUES AFFECTING SOME LOCATIONS. AREAS IN THE NORTH SHOULD
CLEAR UP LATER TODAY, WHILE SOUTHERN AREAS WILL LIKELY SEE SMOKE GET
WORSE.

NU...THE LOW PRESSURE SYSTEM IN FOXE BASIN WILL PRODUCE SHOWERS TODAY
IN COMMUNITIES IN THE AREA WITH NO SIGNIFICANT ACCUMULATIONS
EXPECTED. THIS LOW WILL SLOWLY PUSH EAST OVER THE NEXT 36 HOUR AND
BRING CONVECTIVE SHOWERS TO SOUTHERN BAFFIN ISLAND ON MONDAY EVENING.

FOG WILL CONTINUE IN THE HIGH ARCTIC AND EASTERN BAFFIN ISLAND
COMMUNITIES. FOR THE HIGH ARCTIC THE PATTERN DOESN'T REALLY CHANGE
UNTIL MID-WEEK.

END/LUZNY/PATTEN