173
FOCN45 CWWG 271900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT WEDNESDAY MAY
27 2026.
ALERTS IN EFFECT...YELLOW HEAT WARNINGS FOR EASTERN ALBERTA, MUCH OF
SOUTHERN SASKATCHEWAN, AND PORTIONS OF SOUTHERN MANITOBA. FREEZING
RAIN WARNING FOR RESOLUTE.
OVERVIEW...ALOFT TODAY, AN UPPER TROUGH SITS OVER NORTHERN BRITISH
COLUMBIA AND DROPS SOUTH INTO A BROAD UPPER LOW SITTING OVER THE
WESTERN UNITED STATES. EAST OF THIS, AN UPPER HIGH SITS OVER SOUTH
DAKOTA WITH RIDING NORTH INTO THE PRAIRIES AND SOUTHERN ARCTIC.
CONTINUING EAST, A COMPLEX OF UPPER LOWS CAN BE FOUND WITH ONE NEAR
KINNGAIT, NU, ONE OVER WESTERN QUEBEC, AND ANOTHER OVER EASTERN
QUEBEC. IN THE HIGH ARCTIC, AN UPPER TROUGH SITS OVER VICTORIA ISLAND
WITH AN UPPER HIGH TO ITS EAST OVER NORTHERN BAFFIN ISLAND WITH A
RIDGE THAT EXTENDS NORTH OVER THE CANADIAN ARCTIC ARCHIPELAGO.
AT THE SURFACE, A 1008 MB LOW PRESSURE CENTRE SITS ALONG THE WESTERN
COAST OF THE CANADIAN ARCTIC ARCHIPELAGO WITH THE ARCTIC FRONT
SWEEPING SOUTH-SOUTHWEST AS AC OLD FRONT AND SOUTHEAST TOWARDS HUDSON
BAY AS A WARM FRONT. EAST OF THIS, A 1036 MB HIGH SITS OVER BAFFIN
BAY WITH RIDGING SOUTH TO THE LABRADOR SEA AND WEST ACROSS NORTHERN
BAFFIN ISLAND THEN ARCING SOUTH ALONG THE KIVALLIQ COAST AND INTO
MANITOBA. TO THE SOUTH, A 1004 MB LOW SITS OVER CENTRAL MONTANA WITH
A WARM FRONT THAT LIFTS NORTH INTO ALBERTA THEN CURLS SOUTHEAST
ACROSS SASKATCHEWAN INTO SOUTHWEST MANITOBA THEN EAST ACROSS THE
GREAT LAKES. LASTLY, A 1007 MB LOW SITS OVER NEW BRUNSWICK WITH A
COLD FRONT WEST-SOUTHWESTS AND A WARM FRONT SOUTHEAST.
DISCUSSION...
WESTERN PRAIRIES...HEAT WARNINGS CONTINUE OVER EASTERN ALBERTA, AND
HAVEN'T BEEN EXPANDED OR PARED BACK TODAY WITH UPPER RIDGING
REMAINING RATHER STATIONARY. HIGH TEMPERATURES WILL RANGE FROM 30
JUST EAST OF THE METROS TO POSSIBLY 36 IN MEDICINE HAT, WITH LOW
TEMPERATURES IN THE MID TEENS. GUIDANCE HAS BEEN CONSISTANT SHOWING
THE HEATWAVE BREAKING THIS WEEKEND, AT LEAST IN THIS PROVINCE.
THUNDERSTORMS EXPECTED TODAY NEAR THE FOOTHILLS AND NEAR THE AB/SK
BORDER ALONG SURFACE TROUGH. WITH CAPE VALUES EXPECTED TO BE NEAR
1000 J/KG AND 0 TO 6 KM SHEAR IN THE 20S, WE CAN SEE SOME MULTICELLS.
THE NUMEROUS GUSTS LASTING WELL INTO LAST NIGHT IS INDICATIVE OF THE
POTENTIAL FOR DOWNBURSTS/MICROBURSTS THIS AFTERNOON, PRESENT
THROUGHOUT SOUTHERN ALBERTA, BUT PARTICULARLY CONCERNING OVER EAST
CENTRAL REGIONS, WHERE THUNDERSTORMS COULD TRIGGER AND DCAPE VALUES
ARE ANTICIPATED TO BE VERY HIGH IN THE HOT ENVIRONMENT.
EASTERN PRAIRIES...THE CONVECTIVE THREAT WILL SHIFT WEST TODAY,
LEAVING THE WESTERNMOST PORTIONS OF SASKATCHEWAN WITH ANY
THUNDERSTORM CONCERNS. AN AXIS OF MLCAPE WILL DEVELOP ALONG AND WEST
OF THE ALBERTA/SASKATCHEWAN BORDER THIS AFTERNOON, AND THUNDERSTORM
ACTIVITY WILL BE TRIGGERED THIS AFTERNOON BY A SHORTWAVE LIFTING
NORTH INTO THE UPPER RIDGE. MLCAPE WILL DROP FROM NEAR 500 J/KG ALONG
THE BORDER TO NEARLY NOTHING QUICKLY MOVING INTO SASKATCHEWAN, WHICH
WILL RESTRICT THUNDERSTORMS INTO THE WESTERN TIER OF REGIONS IN THE
PROVINCE. WITH LOW CAPE AND BULK SHEAR VALUES OF 15 TO 20 KNOTS,
THERE IS LITTLE SEVERE WEATHER THREAT EXPECTED. ONE CONCERN WITH ANY
CONVECTION TODAY WILL AGAIN BE THE DRY LOW-LEVELS AND HIGH DCAPE
VALUES; DCAPE WILL CLIMB OVER 1,000 J/KG TODAY, MEANING ANY SHOWERS
OR THUNDERSTORMS THAT DEVELOP COULD PRODUCE STRONG TO SEVERE WIND
GUSTS, BUT IT IS NOT CONSIDERED AN ORGANIZED THREAT AT THIS TIME.
A SECONDARY AXIS OF INSTABILITY WILL DEVELOP OVER SOUTHEAST
SASKATCHEWAN INTO THE DAKOTAS, BUT A CAPPING INVERSION AND LACK OF
SYNOPTIC LIFT OR TRIGGERING FEATURE SHOULD PREVENT ANY CONVECTION
FROM DEVELOPING.
ON THURSDAY, A SEVERE THUNDERSTORM THREAT WILL REDEVELOP IN WESTERN
SASKATCHEWAN AS THE INSTABILITY BEGINS TO BUILD BACK EAST. MLCAPE
VALUES WILL CLIMB BACK TOWARDS 1,000 J/KG WITH 20 TO 25 KNOTS OF BULK
SHEAR AND A SURFACE TROUGH SHOULD HELP FOCUS CONVECTIVE INITIATION.
THUNDERSTORM ACTIVITY WILL TRACK EAST LATER IN THE DAY AND COULD
REACH WEST-CENTRAL MANITOBA IN THE EVENING. OVER WEST CENTRAL SK
NORTH TO BUFFALO NARROWS, MOISTURE POOLING ALONG THE TROUGH IS
BRINGING PWAT VALUES UP TO 30 MM OR SO ALONG WITH DECREASING STORM
MOTIONS IN THE 5 TO 10 KNOT RANGE. HERE, THERE IS POTENTIAL FOR
POCKETS OF HEAVY RAIN GIVEN THE GENERALLY UP AND DOWN NATURE OF
THESE SLOWER MOVING CELLS.ELSEWHERE, GIVEN THE CAPE VALUES AND MILD
SHEAR, MARGINALLY SEVERE HAIL AND WIND GUSTS WILL BE THE THREATS
FROM ANY STORMS THAT DEVELOP ON THURSDAY AFTERNOON.
DAYTIME HIGHS IN THE LOW TO MID-30S CONTINUE TO SPREAD EAST AND NORTH
ACROSS THE PRAIRIES AS THE HEAT BUILDS UNDER THE UPPER RIDGE IN PLACE
OVER THE REGION. THIS HEAT WILL CONTINUE TO BUILD THROUGH
SASKATCHEWAN TODAY AND BEGIN TO SPREAD INTO MANITOBA TOMORROW.
OVERNIGHT LOWS WILL RANGE FROM THE UPPER TEENS TO LOW 20S THROUGHOUT
MUCH OF THE SOUTHERN PRAIRIES.
A YELLOW HEAT WARNING IS IN EFFECT FOR A SIGNIFICANT PORTION OF
SOUTHERN SASKATCHEWAN THIS MORNING; THIS WARNING WILL SHIFT EAST WITH
THE HEAT THROUGH THE COURSE OF THE WEEK. PORTIONS OF THIS HEAT
WARNING MAY BE UPGRADED TO AN ORANGE HEAT WARNING THIS AFTERNOON.
THE HEAT WILL PERSIST THROUGH THE REST OF THE WEEK, THEN GRADUALLY
EASE FROM WEST TO EAST THROUGH THE EARLY PART OF NEXT WEEK.
IN NORTHERN MANITOBA, VISIBILITIES HAVE STARTED TO IMPROVE ALONG THE
HUDSON BAY COAST. THE FOG ADVISORY WAS ENDED THIS MORNING FOR
CHURCHILL AND YORK.
LASTLY, A FEW FOREST FIRES HAVE DEVELOPED OVER THE LAST 24 TO 48
HOURS AND HAVE BEGUN TO PRODUCE SMOKE PLUMES IMPACTING PARTS OF THE
REGION. A FEW SMALLER FOREST FIRES IN WEST-CENTRAL MANITOBA HAVE
PRODUCED A SMOKE PLUME THAT DROVE AQHI+ VALUES UP INTO THE 7 TO 10
RANGE THROUGH PORTIONS OF EAST-CENTRAL SASKATCHEWAN. A YELLOW AIR
QUALITY WARNING WAS ISSUED FOR THE NIGHT PERIOD; THE WARNING WAS
ENDED EARLY WEDNESDAY AS WINDS SHIFT, PICK UP, AND THE
BOUNDARY LAYER IS ABLE TO VENTILATE. THESE FIRES WILL NEED TO BE
WATCHED IN THE COMING DAYS, THOUGH, AS HEAT BUILDS AND THEY PRODUCED
A SURPRISING AMOUNT OF SMOKE THAT REMAINED CLOSE TO THE SURFACE IN
THE REGION.
WEST OF THIS, AN INTENSE FOREST FIRE BECAME VISIBLE SOUTHWEST OF
PRINCE ALBERT YESTERDAY. IT WAS PRODUCING A NARROW BUT INTENSE SMOKE
PLUME BUT IT DID NOT SEEM TO HAVE AN ADVERSE EFFECT ON AIR QUALITY
SENSORS IN ANY DOWNSTREAM FLOW THAT WE COULD FIND. THAT SAID, THE
INTENSITY IS CONCERNING AND WITH INTENSE HEAT BUILDING INTO THE
REGION THIS WEEK, IT WILL LIKELY NEED TO BE WATCHED AND RESULT IN AIR
QUALITY WARNINGS AT SOME POINT THIS WEEK.
NWT...MESSY WEATHER AROUND A DEVELOPING LOW IN THE SATHU AND FRONTAL
BOUNDARY DRAPED ACROSS THE NORTH, WITH SOME RISK OF THUNDERSTORMS IN
THE FORMER REGION AND MIXED PRECIPITATION IN THE LATER. A FEW CM OF
SNOW ACCUMLUATION IS EXPECTED IN PAULATUK TOWARDS THE END OF TONIGHT
AND INTO THURSDAY.
FARTHER SOUTH, THERE IS A CHANCE OF NON-SEVERE THUNDERSTORMS FOR MUCH
OF THE SAHTU AS WELL AS AREAS NORTH OF YELLOWKNIFE WEDNESDAY
AFTERNOON. SOUTH OF GREAT SLAVE LAKE SHOULD BE LARGELY JUST TCU
SHOWERS BUT SOME ISOLATED LIGHTNING STRIKES ARE POSSIBLE IN THIS AREA
AS WELL. FOG COULD AFFECT COMMUNITIES AROUND THE ARCTIC COAST, THOUGH
THIS IS NEVER VERY EASY TO PREDICT IN SPRING.
NUNAVUT...MIXED PHASE PRECIPITATION WILL TAPER OFF TODAY OVER
SOUTHWESTERN BAFFIN ISLAND AS A SHORTWAVE CONTINUES TO SLUMP SOUTH
TOWARDS THE UNGAVA PENINSULA. QUIET WEATHER WILL SETTLE OVER BAFFIN
ISLAND FOR A COUPLE DAYS.
FURTHER WEST, WARMER AIR PUSHING INTO THE KIVALLIQ WILL SPREAD AN
AREA OF RAIN INTO THE REGION OVERNIGHT INTO THURSDAY, EVENTUALLY
LIFTING NORTH INTO NORTHERN BAFFIN ISLAND BY FRIDAY. ACCUMULATIONS
WILL VARY, BUT 5 TO 15 MM IS LIKELY ALONG THE AXIS OF HEAVIEST RAIN
WHICH LOOKS TO RUN FROM ARVIAT (CYEK) TO BAKER LAKE (CYBK).
FOG CONCERNS WILL SHIFT NORTH INTO THE KIVALLIQ COAST TODAY AS THE
WINDS SWING AROUND FROM NORTHERLY TO SOUTHEASTERLY; STRATUS AND FOG
PATCHES WILL STREAM ONSHORE TODAY. THE ONSHORE FLOW WILL CONTINUE FOR
A FEW DAYS AS THE WARMER AIR PUSHES INTO THE REGION; LOW CLOUD AND
FOG PATCHES COULD BE A CONCERN ALONG THE COAST FOR A WHILE YET.
FOG COULD ALSO AFFECT CAMBRIDGE BAY FOR THE NEXT COUPLE DAYS, THOUGH
IT WASN'T AS PERSISTANT AS ANTICIPATED WHEN IT SET IN THIS MORNING.
TONIGHT, A FRONTAL BOUNDARY AND A PUSH OF WARM ARE WILL CRAWL TOWARDS
RESOLUTE. WE'RE LESS CONCERNED WITH BLOWING SNOW GIVEN THE WARM
TEMPERATURES, NEAR 24 HOUR SUNLIGHT, AND LACK OF RECENT SNOW, AND THE
GRADIENT DOESN'T QUITE SEEM TIGHT ENOUGH TO WARRANT A WIND WARNING,
BUT THERE'S POTENTIAL FOR A SOLID HALF DAY OF LIGHT FREEZING RAIN,
WITH ACCRETION VALUES POSSIBLE REACHING 5 MM OR MORE. THIS, IN
CONJUCTION WITH GUSTS UP TO 80 KM/H WINDS, COULD MAYBE MANAGE TO
CAUSE POWER OUTAGES IN THE REMOTE COMMUNITY.
END/VROLIJK/STAMMERS/KNIGHT/MARK
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page