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FOCN45 CWWG 051900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT FRIDAY JUNE
5 2026.
ALERTS IN EFFECT...SEVERE THUNDERSTORM WATCH FOR CENTRAL AND EASTERN
ALBERTA. AIR QUALITY WARNINGS FOR PARTS OF THE SOUTHERN NWT.
OVERVIEW...ALOFT THIS AFTERNOON, AN UPPER LOW SITS OFF THE COAST OF
BRITISH COLUMBIA, CENTRED NEAR HAIDA GWAII. A STRONG WESTERLY FLOW
LIFTS FROM WASHINGTON STATE NORTHEAST ACROSS THE BRITISH COLUMBIA
INTERIOR AND BECOMES DIFFLUENT OVER ALBERTA. TO THE EAST OF THIS, A
SLACK FLOW SITS OVER MUCH OF THE CENTRAL AND EASTERN PRAIRIES WITH A
WEAK SHORTWAVE OVER SE SASKATCHEWAN AND AN UPPER LOW OVER NW ONTARIO.
FURTHER NORTH, THE POLAR VORTEX SITS OVER THE EASTERN ARCTIC OCEAN
WITH A BROAD CYCLONIC FLOW ENCOMPASSING MUCH OF CANADA'S ARCTIC
REGION.
AT THE SURFACE, A 998 MB LOW SITS NEAR GREAT SLAVE LAKE WITH A TROUGH
WEST INTO NORTHEASTERN BC AND SOUTH THROUGH EASTERN ALBERTA INTO
SOUTHWEST SASKATCHEWAN. EAST OF THIS, A 1009 MB HIGH SITS OVER
SOUTHAMPTON ISLAND. EAST OF THIS, A 1001 MB LOW SITS NEAR KINNGAIT,
NU WITH A COLD FRONT DRAPED WEST ACROSS NORTHERN KIVALLIQ AND THROUGH
NORTHERN NORTHWEST TERRITORIES. IN THE SOUTH, A 1004 MB LOW SITS OVER
NORTHWEST ONTARIO WITH A COLD FRONT THAT SWEEPS SOUTHWEST INTO THE
NORTHERN PLAINS OF THE UNITED STATES THEN CONTINUES INTO THE MOUNTAIN
STATES. IN THE EAST, A 1017 MB HIGH SITS OVER QUEBEC WITH RIDGING
WEST ACROSS EASTERN HUDSON BAY INTO CENTRAL MANITOBA.
DISCUSSION...
AB/NORTHERN SK...ANOTHER SHORTWAVE IS CROSSING THE ROCKY MOUNTAINS
TODAY. WITH FALLING HEIGHTS, EXCELLENT JET SUPPORT, AND 0-6 KM SHEAR
IN THE 30 TO 40 KNOT RANGE, THE SHORTWAVE SUPPORT ORGANIZED STRONG TO
SEVERE THUNDERSTORMS OVER CENTRAL ALBERTA TODAY. THUNDERSTORMS HAVE
ALREADY BEGUN WEST OF EDMONTON, AND MORE DEVELOPMENT IS EXPECTED BY
EARLY THIS AFTERNOON. SOME ISOLATED CELLS, PERHAPS A SUPERCELL, WILL
LIKELY COALESCE INTO A LINE AND MARCH EASTWARDS THROUGH ALBERTA.
HAIL IS THE PRIMARY THREAT, THOUGH IMPACTS FROM WIND AND, GIVEN THE
VERY SATURATED SURFACE IN SOME PLACES, RAIN, CAN'T BE RULED OUT.
THUNDERSTORMS ARE ALSO ANTICIPATED AS FAR SOUTH AS CALGARY AND MOST
AREAS NORTHWARDS TO FORT MCMURRAY, AS WELL AS PORTIONS OF NORTHERN
SASKATCHEWAN.
A REASONABLY STRONG SOUTHWESTERLY FLOW WILL KEEP THINGS DRY AND A BIT
WINDY, WITH GUSTS AS HIGH AS 70 KM/H, FOR AREAS FURTHER SOUTH.
SOUTHERN SK/MB...TODAY'S PRIMARY THUNDERSTORM THREAT FOR THE EASTERN
PRAIRIES WILL ORGANIZE THROUGH WESTERN SASKATCHEWAN THIS AFTERNOON.
A SHORTWAVE EJECTING OUT OF SOUTHERN ALBERTA WILL SUPPORT THE
DEVELOPMENT OF A WEAK SURFACE LOW THAT WILL LIFT FROM THE
LLOYDMINSTER AREA TOWARDS MEADOW LAKE LATE THIS AFTERNOON. MLCAPE
VALUES WILL BE LIMITED AT 500 TO 1,000 J/KG, BUT A STRONG
SOUTHWESTERLY JET ALOFT MOVING INTO THE REGION WILL RESULT IN 40 TO
50 KNOTS OF 0-6KM SHEAR. THE DOMINANT SHEAR PROFILE WILL TEND TOWARDS
UNIDIRECTIONAL SHEAR, RESULTING IN MULTI-CELLULAR THUNDERSTORMS THAT
TRACK NORTHEAST WITH THE PRIMARY JET FORCING.
THREATS ARE TRICKY TO PIN DOWN GIVEN THE RESTRICTED CAPE VALUES; TO
AN EXTENT THE STRONGER SHEAR WILL OFFSET THE LACK OF ENERGETICS.
PRIMARY THREATS THIS AFTERNOON WILL BE LARGE HAIL AND DAMAGING WIND
GUSTS. AN ISOLATED TORNADO IS POSSIBLE, BUT THAT RISK WILL BE MOST
LIKELY ASSOCIATED WITH THE SHORTWAVE LIFTING THROUGH THE REGION AND
NOT THE SURFACE TROUGH OUT AHEAD OF IT.
EXPECT AN INITIAL WAVE OF CONVECTION ALONG THE SURFACE TROUGH
EXTENDING SOUTH FROM THE NWT LOW, LIKELY INITIATING ALONG A
NORTH-SOUTH LINE NEAR THE ALBERTA/SASKATCHEWAN BORDER, FOLLOWED BY A
STRONGER BAND OF THUNDERSTORMS THAT DEVELOP ALONG THE FORWARD FLANK
OF THE ADVANCING SHORTWAVE. THESE STORMS WILL LIFT NORTHEAST THROUGH
THE EVENING, BLOSSOMING INTO A BROADER AREA OF SHOWERS OVERNIGHT IN
THE NORTHERN PRAIRIES.
AS IT LIFTS NORTH, A NEW AREA OF CONVECTION IS EXPECTED TO DEVELOP IN
MONTANA AND LIFT NORTHEAST INTO SOUTHEASTERN SASKATCHEWAN, POWERED BY
A STRENGTHENING LLJ AS A SURGE OF WARMER AIR PUSHES INTO EASTERN
SASKATCHEWAN AND MANITOBA. MUCAPE WILL BE LIMITED AND IT IS NOT
EXPECTED TO BRING ANY SEVERE WEATHER RISK.
ON SATURDAY, A POTENT SEVERE WEATHER RISK WILL DEVELOP OVER EASTERN
SASKATCHEWAN ALONG A STRONG WARM FRONT THAT WILL ORIENT ITSELF ACROSS
THE REGION, STRETCHING FROM A LOW IN MONTANA. THE ENVIRONMENT IN THIS
REGION SHOWS MLCAPE VALUES OVER 2500 J/KG, COUPLED WITH BULK SHEAR
VALUES OF 30 TO 50 KTS AND SUBSTANIALLY VEERING WITH HEIGHT WIND
PROFILES. THIS WILL LEAD TO THE DEVELOPEMNT OF AN AREA OF SEVERE
THUNDERSTORMS OVER SOUTHEAST SASKATCHEWAN AND PARTS OF WESTERN
MANITOBA SATURDAY AFTERNOON AND EVENING. STRONG SUPERCELLS ARE LIKELY
IN THIS AREA WITH ALL SEVERE WEATHER THREATS POSSIBLE, INCLUDING
STRONG WINDS, LARGE HAIL, AND TORNADOS. THE TORNADO RISK WILL BE
HIGHEST IN A SMALLER AREA EAST OF REGINA, NORTH OF ESTEVAN AND EAST
TO YORKTON, WHERE SRH VALUES OF 0 TO 1 KM AND 0 TO 3 KMS ARE 150 AND
250 METRES SQUARED PER SECOND SQUARED RESPECTIVELY. THAT BEING SAID,
A CAPPING INVERSION MAY INHIBIT SUPERCELL DEVELOPMENT IN AREAS CLOSER
TO THE INTERNATIONAL BORDER. THESE SEVERE THUNDERSTORMS WILL CONTINUE
INTO WESTERN MANITOBA THROUGH THE EVENING HOURS SUPPORTED BY A
POWERFUL LLJ OF 30 TO 40 KTS, ALTHOUGH THE STORM MODE WILL BECOME
MORE LINEAR AS THE EVENING PROGRESSES.
SEASONAL TEMPERATURES WILL CONTINUE ACROSS THE SOUTHERN PRAIRIES FOR
ANOTHER DAY, THEN HEAT WILL BEGIN TO BUILD INTO THE REGION. DAYTIME
HIGHS WILL CLIMB INTO THE UPPER 20S OR LOW 30S THIS WEEKEND ACROSS
SOUTHEAST SASKATCHEWAN AND SOUTHERN MANITOBA. HUMIDITY WILL BE
LIMITED ON SATURDAY, BUT STRONG MOISTURE RETURN WILL DRIVE HIGH DEW
POINT AIR INTO SOUTHERN MANITOBA FOR SUNDAY. HUMIDEX VALUES WILL
CLIMB INTO THE UPPER 30S OVER SOUTHERN MANITOBA ON SUNDAY.
TEMPERATURES WILL RETURN TOWARDS SEASONAL VALUES TO START NEXT WEEK.
NWT...WILDFIRE SMOKE CONTINUES TO DRIFT AROUND THE GREAT SLAVE LAKE
REGION FROM A FIRE NORTH OF FORT SMITH. WITH AN EASTERLY FLOW HAVING
DEVELOPED LAST NIGHT, SMOKE MOVED OUT OF LUTSEL K'E BUT MOVED AS FAR
EAST AS FORT PROVIDENCE. WE THINK, TENTATIVELY, THAT SMOKE WILL MIX
OUT OF SOME AREAS THIS MORNING AND EVENTUALLY THE STAGNENT FLOW WILL
TURN NORTHERLY AS A LOW DROPS SOUTH OF THE 60TH PARALLEL. THIS WITH
SOME RAIN WOULD CLEAR THE AIR FOR MOST AREAS EXCEPT SOME PARTS OF THE
FORT SMITH-THEBACHA REGION.
NUNAVUT...A MIX OF RAIN AND SNOW WILL SPREAD THROUGH THE KIVALLIQ AND
NORTHERN BAFFIN ISLAND OVER THE NEXT COUPLE OF DAYS AS MOISTURE
STREAMS NORTHEAST ALONG AN ADVANCING COLD FRONT INTO THE REGION.
NO NOTABLE ACCUMULATIONS ARE EXPECTED THROUGH THE KIVALLIQ AND
NORTHERN BAFFIN ISLAND.
END/COLANGELO/LUZNY/GRIFFITH
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