847
FOCN45 CWWG 301200
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT TUESDAY JUNE
30 2026.
ALERTS IN EFFECT...RAINFALL WARNING FOR WESTERN MANITOBA. HEAT AND
AIR QUALITY WARNINGS FOR SOUTHERN NT. AIR QUALITY WARNING FOR
NORTHERN SASKATCHEWAN AND MUCH OF ALBERTA. HEAT WARNING FOR NORTHERN
ALBERTA AND NORTHWESTERN SASKATCHEWAN.
OVERVIEW...ALOFT, AN UPPER LOW IS OVER ALASKA WITH TROUGHING
SOUTHWARD THROUGH THE YUKON AND BC. AN UPPER RIDGE OF HIGH PRESSURE
EXTENDS FROM THE EASTERN PACIFIC THROUGH SOUTHERN BC AND INTO
NORTHERN ALBERTA AND THE CENTRAL ARCTIC. A COMPLEX OF UPPER LOWS WITH
VARIOUS EMBEDDED SHORTWAVES ARE OVER SOUTHERN SASKATCHEWAN. A STRONG
SOUTHWESTERLY JET IS LOCATED OVER THE AMERICAN GREAT PLAINS AND
EXTENDS INTO SOUTHWESTERN MANITOBA/NORTHWESTERN ONTARIO. AN UPPER
RIDGE OF HIGH PRESSURE IS OVER ONTARIO AND QUEBEC. AN UPPER LOW IS
OVER THE HIGH ARCTIC WITH TROUGHING SOUTHWARD THROUGH DAVIS STRAIT.
ANOTHER UPPER LOW IS OVER THE SOUTHERN TIP OF GREENLAND.
AT THE SURFACE, RIDGING DOMINATES THE EASTERN PACIFIC. AN INTENSE,
OCCLUDED LOW PRESSURE SYSTEM LIES OVER WESTERN MANITOBA WITH ITS
ASSOCIATED FRONTAL WAVE WELL OFF TO THE EAST OVER ONTARIO.
LOW PRESSURE IS OVER WESTERN NWT. HIGH PRESSURE IS OVER THE BOOTHIA
PENINSULA WITH RIDGING NORTHWARD INTO THE HIGH ARCTIC AND
SOUTHEASTWARD ACROSS HUDSON BAY AND INTO NORTHERN QUEBEC.
LOW PRESSURE IS OVER SOUTHERN BAFFIN ISLAND.
DISCUSSION...
AB/NRN SK...A SPLIT FLOW REMAINS IN THE REGION WITH EASTERLIES OVER
NORTHERN SASKATCHEWAN BECOMING NORTHWESTERLIES OVER SOUTHERN ALBERTA
AND SOUTHERLIES OVER NORTHERN ALBERTA. THIS HAS FILTERED SMOKE FROM
THE NUMEROUS FIRES FROM THE EASTERN PRAIRIES INTO ALBERTA.
AIR QUALITY HAS GENERALLY BEEN HOVERING IN THE MODERATE TO HIGH RISK
RAINGE OVER AREAS WHERE THE WARNING IS OUT, AND IT APPEARS TOO SOON
TO END IT IN ANY OF THESE REGIONS AT THIS JUNCTURE. THE FLOW WILL
SLACKEN OVER THE NEXT COUPLE DAYS AND AIR QUALITY SHOULD SLOWLY
IMPROVE OVER THE NEXT 48 HOURS OR SO, WITH THE EXCEPTION OF NORTHERN
SASKATCHEWAN WHERE MORE ACTIVE FIRES ARE LOCATED.
AN UNSTABLE AND FAIRLY MOIST AIRMASS WILL HANG OVER MUCH OF THE
PROVINCE, WITH THE MOST MOISTURE AND HUMIDITY OVER THE PEACE AND
GRANDE PRAIRIE REGION WHERE NEARLY 2000 J/KG OF MLCAPE AND DEWPOINTS
IN THE MID TEENS MAY BE IN PLACE. IN THIS NORTHWESTERN CORNER OF THE
PROVINCE, IT'S A BIT OF A TOSS UP IF SHEAR WILL BE ENOUGH TO MAINTAIN
STORMS, BUT WITH SURFACE TROUGHING TO FOCUS CONVECTION, DCAPE VALUES
TOPPING 1000 J/KG IN SOME AREAS, AND THE AFORMENTIONED VERY UNSTABLE
AIRMASS, EVEN PULSE STORMS COULD BRING WIND, RAIN OR HAIL HAZARDS TO
THIS AREA.
SMOKE MAY AT LEAST SLOW HEATING AND INITAITON BUT DIDN'T PROVE ENOUGH
TO STOP SEVERE THUNDERSTORM DEVELOPMENT YESTERDAY.
ANOTHER AREA OF MODERATE INSTABLITY AND SHEAR WILL BE ON THE OTHER
SIDE OF THE DIFFLUENT FLOW OVER SOUTHERN ALBERTA. LESS IMPRESSIVE
THAN IN THE NORTH, WIND AND PERHAPS HAIL ARE THE PRIMARY THREATS HERE
IN MULTICELLS.
NEARER THE UPPER RIDGE OVER THE NORTHERN PRAIRIES, HEAT WARNINGS
REMAIN IN EFFECT, THOUGH TOO MUCH SMOKE MAY PLAY SOME ROLE IN HIGH
TEMPERATURES IN THE REGION.
SK/MB...GENERALLY UNSETTLED, ALBEIT MUCH QUIETER DAY ON TAP IN THE
WAKE OF MONDAY'S INTENSE THUNDERSTORMS THAT GAVE STRONG WINDS AND
HEAVY RAINFALL TO MUCH OF SOUTHERN MANITOBA. ISOLATED TO SCATTERED
THUNDERSTORMS WILL BE POSSIBLE ACROSS MUCH OF SOUTHERN SASKATCHEWAN
AS WELL AS SOUTHERN AND CENTRAL MANITOBA ON TUESDAY AS GENERAL
INSTABILITY REMAINS IN THE WESTERLY FLOW IN THE WAKE OF THE LOW
PRESSURE SYSTEM NOW OVER WESTERN MANITOBA. MEAGRE INSTABILITY AND
SHEAR WILL RESULT IN DISORGANIZED, NON-SEVERE THUNDERSTORMS. A ROGUE
SEVERE STORM CANNOT BE RULED OUT OVER EXTREME SOUTHWESTERN
SASKATCHEWAN WHERE SLIGHTLY HIGHER INSTABILITY AND SHEAR EXISTS BUT
CONFIDENCE IS TOO LOW FOR A YELLOW RISK AREA AT THIS TIME. THERE WILL
ALSO BE A RISK OF FUNNEL CLOUDS MOSTLY OVER CENTRAL MANITOBA IN THE
VICINITY OF THE UPPER LOW.
HEAVY RAIN CONTINUES ABOUT THE DEEP, OCCLUDED LOW PRESSURE SYSTEM
OVER WESTERN AND CENTRAL MANITOBA. A FURTHER 15 TO 25 MM IS FORECAST
ON TUESDAY. THIS SYSTEM WILL STALL AS IT GRADUALLY WEAKENS, GIVING
ADDITIONAL SHOWERS AND THUNDERSHOWERS ON WEDNESDAY. A RAINFALL
WARNING CONTINUES OVER THE PARKLANDS OF WESTERN MANITOBA AS THE
REGION REMAINS PARTICULARLY VULNERABLE TO ANY ADDITIONAL
PRECIPITATION. ACCUMULATING RAINFALL IS ALSO FORECAST ACROSS THE
INTERLAKE AND CENTRAL MANITOBA ON TUESDAY INTO WEDNESDAY.
IN NORTHERN MANITOBA, WILDFIRE SMOKE WILL CONTINUE TO PROPAGATE
THROUGH MUCH OF THE REGION, GRADUALLY SHIFTING TO BE A CONCERN FOR A
COUPLE AREAS ALONG THE SASKATCHEWAN BORDER AS AN EASTERLY FLOW
DEVELOPS -- MAINLY PARTS OF THE THOMPSON, LYNN LAKE, AND FLIN FLON
REGIONS.
NUNAVUT...ABOVE SEASONAL TEMPERATURES WILL CONTINUE WELL INTO NEXT
WEEK, BUT MOST SITES LOOK TO REMAIN BELOW HEAT WARNING LEVEL
THRESHOLDS.
A FEW SCATTERED SHOWERS WILL FALL OVER SOUTHERN BAFFIN ISLAND AS A
LOW PRESSURE SYSTEM REMAINS OVER THE AREA FOR THE NEXT 12 TO 24
HOURS.
FINALLY, A LOW PRESSURE SYSTEM PASSING THROUGH THE HIGH ARCTIC MAY
GIVE GUSTY WINDS TO ARCTIC BAY AND POND INLET LATE WEDNESDAY INTO
WEDNESDAY NIGHT.
NWT...SMOKE CONTINUES TO DRIFT IN THE AREA BOTH FROM LOCAL FIRES
WHICH HAVE PROMPTED EVACUATION NOTICES AND FROM FIRES BACK IN
SASKATCHEWAN. AIR QUALITY RISK IS GENERALLY SITTING AROUND MODERATE
IN THE REGION FOR NOW BUT IT REMAINS TOO EARLY TO END THE AIR QUALITY
WARNING HERE.
THE SEVERE THREAT MENTIONED PREVIOUSLY OVER NORTHWESTERN ALBERTA WILL
BE POKING INTO THE NWT. SHEAR WILL BE STRONG ENOUGH TO SUSTAIN
MULTICELLS HERE, AND THERE'S SOME CHANCE OF HAZARDOUS WEATHER BETWEEN
FORT PROVIDENCE AND FORT SIMPSON.
HEAT WARNINGS AROUND GREAT SLAVE LAKE WILL CONTINUE UNTIL THURSDAY OR
FRIDAY WITH THE INFLUENCE OF THE UPPER RIDGE EAST OF THAT AREA.
END/STAMMERS/BATE
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