FOCN45 CWWG 181200

SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM

PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT SATURDAY JULY

18 2026.



ALERTS IN EFFECT...AIR QUALITY WARNINGS FOR THE SOUTHERN NWT,

PORTIONS OF NORTHERN PRAIRIES. HEAT WARNINGS FOR SOUTHERN NWT, PART

OF NORTHERN ALBERTA, SOUTHEASTERN ALBERTA, SOUTHWESTERN SASKATCHEWAN,

PARTS OF NORTHERN SASKATCHEWAN AND PARTS OF SOUTHERN AND CENTRAL

MANITOBA.



OVERVIEW...ALOFT, AN UPPER LOW SITS OVER VANCOUVER ISLAND. AN UPPER

RIDGE EXTENDS FROM THE CENTRAL CONUS NORTHWARDS THROUGH THE CENTRAL

PRAIRIES AND THROUGH NWT TO THE BEAUFORT SEA. UPPER LOW AND TROUGH

OVER THE KITIKMEOT AND A LARGE UPPER LOW COMPLEX CENTERED OFFSHORE OF

LABRADOR WITH TROUHING NORTHWARD THROUGH BAFFIN ISLAND.



AT THE SURFACE, A 1032 SITS IN THE EASTERN PACIFIC WITH WEAK TROUHING

OVER YUKON, NWT, WESTERN NUNAVUT, BC AND ALBERTA. SLACK FLOW OVER THE

EASTERN PRAIRIES. WEAKENING 995 MB LOW IN LABRADOR SEA.



DISCUSSION...



AB...A POTENTIALLY EXPLOSIVE DAY, SEVERE WEATHER WISE. ISOLATED

TORNADIC SUPERCELLS DEVELOPED YESTERDAY EVENING IN THE NRN FOOTHILLS

AIDED BY A 30KT JET AT H500, STRONG BACKED FLOW IN THE BL, AND DEW

POINTS APPROACHING 20 DEG C. THIS IS BUT A PREVIEW OF THE TYPE OF

WEATHER ANTICIPATED FOR SATURDAY.



IN THE UPPER LEVELS, A NEGATIVELY TILTED TROF IS EXPECTED TO CAUSE A

RIDGE BREAKDOWN AS THE H500 JET STRENGTHENS TO NEAR 50 KTS WITH

DIFFLUENT FLOW IN THE EXIT REGION OVER CENTRAL ALBERTA.

IN CONJUNCTION WITH NEAR SFC FLOW OF 10+ KTS FROM THE EAST OR SE,

HODOGRAPHS WILL BE QUITE CURVED. BWD VALUES WILL THEREFORE BE

SUPPORTIVE OF SUPERCELLS, MOST LIKELY OF THE CLASSIC VARIETY.

AN ELEVATED MIXED LAYER HAS ALSO BEEN EVIDENT ON THE STONY PLAIN

SOUNDING OVER THE PAST SEVERAL DAYS WHICH SHOULD ENSURE ENOUGH

DAYTIME HEATING TO REALIZE UNUSUALLY HIGH CAPE VALUES.



TO WIT, RECENT RUNS OF THE RDPS AND HRDPS ARE CONSISTENTLY SUGGESTING

MLCAPE VALUES OF 3000+ J/KG WHICH IS NEARLY UNHEARD OF IN ALBERTA.

THE MAIN QUESTION IS WHERE EXACTLY THE SFC LOW DEVELOPS AS TORNADIC

POTENTIAL WILL BE MAXIMIZED IN THE NE QUADRANT. THE BEST CHANCE FOR

STRONG AND/OR MULTIPLE TORNADOES WILL COINCIDE WITH THE INTERSECTION

OF A DRYLINE AND COLD FRONT. NWP GUIDANCE HAS BEEN GRADUALLY PULLING

THIS FEATURE NORTH AND WEST WITH SUCCESSIVE RUNS, FROM THE SASK

BORDER TOWARD THE EDMONTON METRO AREA.



THIS AREA WILL NEED TO BE MONITORED VERY CLOSELY BY AFTERNOON AS ANY

STORMS THAT FORM IN THIS ENVIRONMENT WILL LIKELY BE DANGEROUS.

IT SHOULD BE NOTED THAT THIS EXACT TYPE OF PATTERN, WHILE RARE, HAS

HISTORICALLY BEEN ASSOCIATED WITH LONG-TRACK, TORNADIC SUPERCELLS.



ELSEWHERE IN THE PROVINCE. SMOKE HAS DRIFTED INTO NORTHERN ALBERTA

FROM THE NWT, AND AIR QUALITY WARNINGS HAVE BEEN ISSUED ACCORDINGLY.

SOME IMPROVEMENT IS POSSIBLE SATURDAY WITH SURFACE FLOW TURNING

WEAKLY SOUTHEAST. HEAT ALSO REMAINS IN NORTHERN ALBERTA UNDER SOME

WEAK UPPER RIDGING FOR THE NEXT 2 TO 3 DAYS, THOUGH SMOKE IN THE AREA

MAY HINDER HIGH TEMPERATURES. A HEAT WARNING IS ALSO IN EFFECT FOR

SOUTHEASTERN ALBERTA WHICH WILL BE NEAR AN UPPER RIDGE THE NEXT TWO

DAYS, SENDING TEMPERATURES INTO THE MID-30S.



SK/MB...A FAVOURABLE SETUP FOR SUPERCELLS TODAY IN WEST CENTRAL

SASKATCHEWAN WITH ALL MODES OF SEVERE WEATHER POSSIBLE INCLUDING

TORNADOES. STRONG 250 AND 500 MB JETS ACROSS SOUTHERN ALBERTA WITH

LEFT EXIT REGION SITTING RIGHT ALONG DEVELOPING WARM FRONT FROM LOW

IN CENTRAL ALBERTA. STRONG VEERING PROFILES, COMBINED WITH 1500 TO

2500 J/KG OF MIXED LAYER CAPE AND 30 TO 35 KNOTS OF 0 TO 6 KM BULK

LAYER SHEAR SIT ON WEST SIDE OF UPPER RIDGES BY 00Z. NORTH BATTLEFORD

TO PRINCE ALBERT AND MEADOW LAKE REGIONS ARE THE MOST FAVOURABLE AREA

OF TORNADIC SUPERCELLS TODAY. FURTHER SOUTH STRETCHING DOWN TO THE

STATES, STRONG WIND SHEARS WITH SLIGHTLY LESS CAPE COULD SEE MORE OF

A QLCS OR MULTICELL SET UP. CAPPING WILL BE AN ISSUE EARLIER IN THE

DAY WITH MORE OF A LATE SHOW EXPECTED. STORMS MAY REMAIN SEVERE OVER

SOUTHERN SASKATCHEWAN THOUGH THE NIGHT. ONGOING MORNING CONVECTION

COULD HAMPER TODAYS SET UP.



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, PORTIONS OF SOUTHWEST

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 THURSDAY AND A LOT OF SMOKE WAS THROWN INTO THE

ATMOSPHERE THERE. WHILE NORTHWEST FLOW HAS BROUGHT ABOUT SOME

IMPROVEMENT FOR COMMUNITIES AROUND GREAT SLAVE LAKE, THE REPRIEVE MAY

BE BRIEF DEPENDING ON HOW MUCH SMOKE FLARES BACK UP TODAY. SMOKE WILL

SWIRL AROUND HIGH PRESSURE IN SOUTHERN PORTIONS OF THE TERRITORY,

KEEPING AIR QUALITY POOR IN THE AREA AT LEAST AT TIMES.



HEAT IS PROGGED TO REMAIN IN PLACE WELL INTO NEXT WEEK GENERALLY.

FORT RESOLUTION AND HAY RIVER MAY FAIL TO REACH THE RECOMMENDED

TEMPERATURE FOR A HEAT WARNING TODAY BUT AREAS INLAND IN THESE

FORECAST REGIONS COULD BE WARMER. THERE IS ALSO THE POSSIBILITY THAT

SMOKE IN SOME AREAS IS SO DENSE THAT HIGH TEMPERATURES WIND UP A

COUPLE DEGREES COLDER THAN FORECAST.



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/LUZNY/VAN LOCHEM