008
FOCN45 CWWG 091200
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT SUNDAY AUGUST
9 2026.
ALERTS IN EFFECT...AIR QUALITY WARNINGS FOR PARTS OF WESTERN ALBERTA.
OVERVIEW...ALOFT TODAY, THE DOMINANT WEATHER FEATURE CONTINUES TO BE
THE LARGE VORTEX OVER HUDSON BAY THAT HAS SEVERAL SHORTWAVES ROTATING
AROUND IT. WEST OF THIS, A WEAK RIDGE-TROUGH PATTERN SITS OVER
WESTERN CANADA WITH AN UPPER TROUGH EXTENDING FROM A COMPACT UPPER
LOW NEAR HAIDA GWAII SOUTH-SOUTHEAST OVER VANCOUVER ISLAND INTO THE
PACIFIC NORTHWEST AND AN UPPER RIDGE EXTENDING NORTH-NORTHWEST FROM
IDAHO/MONTANA TO CENTRAL BRITISH COLUMBIA. A SHORTWAVE ALSO LIES OVER
SOUTHERN AB/SK. IN THE NORTH, AN UPPER LOW SITS ALONG THE COAST OF
THE ARCTIC OCEAN NEAR THE ALASKA/YUKON BORDER WHILE EAST OF THIS A
BROAD UPPER HIGH SITS BETWEEN THE CANADIAN ARCTIC ARCHIPELAGO AND
GREENLAND.
AT THE SURFACE, A 999 MB LOW SITS OVER WESTERN HUDSON BAY WITH AN
OCCLUDED WAVE TO ITS EAST WITH AN APEX OVER THE UNGAVA PENINSULA THAT
HAS A WARM FRONT DRAPED EASTWARDS ACROSS AND A COLD FRONT THAT DROPS
SOUTHWARDS ALONG THE WESTERN QUEBEC COAST THROUGH ONTARIO BEFORE
CURLING WEST ACROSS THE AMERICAN MIDWEST INTO THE NORTHERN PLAINS OF
THE UNITED STATES. IN THE NORTH, A 1013 MB LOW SITS TO THE WEST OF
BANKS ISLAND, NWT WITH A COLD FRONT SOUTHWEST INTO ALASKA AND A WARM
FRONT THAT DROPS SOUTH THROUGH WESTERN CANADA. HIGH PRESSURE LIES
ACROSS AB AND SK AS WELL AS BAFFIN ISLAND.
DISCUSSION...
WESTERN PRAIRIES...AIR QUALITY WILL CONTINUE TO BE AN ISSUE FOR
PORTIONS OF WESTERN ALBERTA, INCLUDING THE MOUNTAIN PARKS AS SMOKE
WILL STREAM IN FROM BC WITH THE WESTERLY FLOW ALOFT. THE QUESTION
THAT REMAINS HOWEVER, IS HOW MUCH SMOKE WILL MIX DOWN TO THE SURFACE.
WITH THE SURFACE FLOW EXPECTED TO REMAIN EASTERLY TODAY, THE
EXPECTATION IS THAT THE SMOKE WILL REMAIN TIED TO THE WESTERN MOST
REGIONS, HOWEVER, THERE IS A CHANCE THAT WE MAY SEE SOME OF THE
HEAVIER SMOKE DRIFT SLIGHTLY FURTHER EAST IN THE LATE AFTERNOON TO
OVERNIGHT HOURS, AS PRECIPITATION FROM AFTERNOON THUNDERSTORMS MIX
DOWN THE SMOKE FROM ALOFT. ALERTS WILL BE UPDATED AS NECESSARY IF AIR
QUALITY BECOMES A SIGNIFICANT RISK.
A NORTHWESTERLY FLOW WITH SEVERAL SHORTWAVES TRAVERSING THE
PROVINCE, WILL CONTINUE TO TRIGGER A FEW THUNDERSTORMS THIS MORNING
THROUGH CENTRAL AND SOUTHEASTERN PARTS OF THE PROVINCE, WHERE CLOUD
TOP COOLING HAS LEAD TO INCREASED INSTABILITY. IN ADDITION, ACROSS
WESTERN PARTS OF THE PROVINCE, WHERE SOME CLEARING HAS DEVELOPED,
FOG PATCHES HAVE DEVELOPED. AS DAYTIME HEATING STARTS TO KICK IN,
THE THUNDERSTORMS SHOULD WEAKEN AND DISSIPATE AND THE FOG WILL
DISPERSE.
A COUPLE OF SHORTWAVES APPROACHING ALBERTA, WILL MOVE INTO CENTRAL
REGIONS THIS AFTERNOON AND INTO THE EARLY EVENING HOURS. IN ADDITION,
A SURFACE TROUGH ALONG THE ALBERTA FOOTHILLS WILL TRIGGER A FEW
THUNDERSTORMS LATE THIS AFTERNOON. AS THE STORMS MOVE OFF THE
FOOTHILLS, THE UPPER TROUGH MOVING IN WILL ALLOW STORMS TO CONTINUE
THOUGH CENTRAL ALBERTA LATE THIS EVENING AND OVERNIGHT AS THE UPPER
SUPPORT IS ABLE TO CARRY THE STORMS FURTHER THE EAST. A FEW OF THESE
STORMS ARE ANTICIPATED TO BECOME SEVERE WITH HAIL AND RAIN BEING THE
PRIMARY THREATS HOWEVER SOME STRONG WIND GUSTS ARE ALSO POSSIBLE.
OVER SOUTHERN ALBERTA, A WARM THERMAL RIDGE AND SMOKE MAY WORK IN
TANDEM TO KEEP CONDITIONS CAPPED TO THUNDERSTORMS TODAY HOWEVER,
THERE IS A SLIGHT RISK THAT A FEW STORMS MAY TRIGGER OFF THE SOUTHERN
FOOTHILLS AS WELL. MOST STORM ACTIVITY SHOULD BE AROUND CALGARY AND
EXTEND NORTHWARD INTO THE PEACE RIVER REGION. THE BEST AREA FOR
SEVERE STORMS WILL BE FROM HINTON TO CALGARY WHERE THE SHEAR PROFILE
WILL BE MORE CONDUCIVE TO SUPPORTING SEVERE THUNDERSTORMS.
EASTERN PRAIRIES...A SHORTWAVE TRACKING OUT OF SOUTHERN ALBERTA
CONTINUES TO SUPPORT AN AREA OF SHOWERS AND THUNDERSTORMS OVER
SOUTHWESTESTERN SASKATCHEWAN EARLY THIS MORNING.
ON SUNDAY AFTERNOON, THUNDERSTORMS WILL BE POSSIBLE OVER SOUTHERN
SASKATCHEWAN ALONG A WEAK INVERTED TROUGH. SBCAPE VALUES WILL CLIMB
INTO THE 500 TO 1,000 J/KG RANGE WITH 50 KNOTS OF DEEP SHEAR THAT
COULD PRODUCE ISOLATED MARGINALLY SEVERE THUNDERSTORMS WITH PRIMARY
HAZARDS OF STRONG WIND GUSTS AND/OR DAMAGING HAIL. THIS ACTIVITY WILL
TAPER OFF OVERNIGHT.
SCATTERED SHOWERS AND PERHAPS THE ODD LIGHTNING STRIKE OR TWO WILL
ALSO ONCE AGAIN DEVELOP ACROSS MUCH OF NORTHERN AND CENTRAL MANITOBA
ON SUNDAY AFTERNOON. WITH ONLY 200 J/KG OF SBCAPE AND 20 KNOTS OF
BULK SHEAR, LIGHTNING STRIKES ARE EXPECTED TO BE FEW AND FAR BETWEEN
WITH NO SEVERE WEATHER THREAT.
ANOTHER SHORTWAVE PUSHING INTO WESTERN SASKATCHEWAN BY MONDAY MORNING
WILL SUPPORT ANOTHER AREA OF SHOWERS AND THUNDERSTORMS ACROSS
SOUTHERN PORTIONS OF THE PROVINCE. NO SEVERE WEATHER IS EXPECTED.
OTHERWISE, HAZY SKIES WILL CONTINUE ACROSS MUCH OF THE SOUTHERN
PRAIRIES AS THE UPPER-LEVEL FLOW SPREADS WILDFIRE SMOKE THROUGH THE
UPPER ATMOSPHERE. AIR QUALITY SHOULD BE LARGELY UNAFFECTED, ALTHOUGH
POOR AIR QUALITY IN WILDFIRE SMOKE IS LIKELY TO DEVELOP OVER PARTS OF
SOUTHWESTERN SASKATCHEWAN EITHER LATER SUNDAY OR MONDAY AS WILDFIRE
SMOKE FROM BRITISH COLUMBIA BEGINS TO SURFACE IN THE AREA.
NT....A FEW SHOWERS IN THE DELTA AND IN THE NORTHERN RIVER REGIONS,
ASSOCIATED WITH A LOW PRESSURE SYSTEM FROM THE BEAUFORT. A VERY
SLIGHT RISK OF A THUNDERSTORM OR TWO ALONG THE LEADING EDGE OF THE
SYSTEM, IN THE WRIGLEY REGION.
AIR QUALITY WILL ALSO BE AN ISSUE IN THE NT, PRIMARILY AROUND AND IN
THE FORT SIMPSON AREA WHERE THE AIR QUALITY HAS BEEN POOR AT TIMES
DUE TO FOREST FIRES NEAR THE COMMUNITY. SMOKE WILL LIKELY BECOME MORE
OF AN ISSUE THIS AFTERNOON AND OVERNIGHT AS THE WIND BECOMES MORE
NORTHERLY AND PUSHES SMOKE FROM THE NEARBY FIRES BACK INTO THE AREA.
NU...WAVES OF PRECIPITATION CONTINUE TO WRAP AROUND THE HUDSON BAY
LOW, THE LATEST OF WHICH WILL PUSH FROM THE UNGAVA PENINSULA TO
SOUTHAMPTON ISLAND BY MIDDAY SUNDAY, THEN WRAP BACK INTO THE KIVALLIQ
ON SUNDAY NIGHT. THIS WILL BRING 5 TO 10 MM OF RAIN TO CORAL HARBOUR
BY SUNDAY EVENING, FOLLOWED BY SIMILAR AMOUNTS IN THE KIVALLIQ
OVERNIGHT SUNDAY INTO MONDAY.
GUSTY WINDS ACROSS THE KIVALLIQ WILL CONTINUE TO EASE ON SUNDAY SAVE
FOR AROUND SOUTHAMPTON ISLAND, HUDSON STRAIT AND INTO THE KINNGAIT
REGION. THE WINDS HERE WILL RE-STRENGTHEN WITH THE NEXT WAVE OF RAIN
MOVING IN AND BRING MORE GUSTY WINDS UP TO 80 KM/H ON SUNDAY MORNING.
THE WINDS WILL EASE ACROSS THE REGION LATER SUNDAY.
IN ADDITION TO THE RAIN, RELATIVELY MILD AIR BEING PUMPED OVER THE
COOLER WATERS OF HUDSON BAY HAS RESULTED IN BROAD AREAS OF FOG ACROSS
THE REGION. FOG PATCHES WILL BE COMMONPLACE ACROSS HUDSON BAY AND THE
ADJACENT COASTAL COMMUNITIES INTO THE WEEKEND.
END/STAMMERS/GREENHOUGH
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