013
FOCN45 CWWG 131900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT SATURDAY
SEPTEMBER 13 2025.
ALERTS IN EFFECT...AIR QUALITY ALERTS FOR PARTS OF THE NORTHWEST
TERRITORIES, NORTHERN ALBERTA, AND NORTHERN SASKATCHEWAN.
SYNOPTIC OVERVIEW...ALOFT, AN UPPER LOW IS OVER THE NORTHERN COAST OF
ALASKA WITH A TROUGH SOUTHWARD TO THE PACIFIC NORTHWEST WITH A
REBOUND INTO AN UPPER RIDGE THAT EXTENDS FROM THE EASTERN PACIFIC
NORTHWEST TO THE BRITISH COLUMBIA/ALBERTA BORDER. AN UPPER LOW SITS
OVER SOUTHERN ALBERTA WITH A TROUGH SOUTHWARD INTO THE WESTERN US
LEAVING THE EASTERN PRAIRIES IN AN ACTIVE SOUTHERLY UPPER FLOW WITH
SEVERAL SHORTWAVES EMBEDDED. AN UPPER RIDGE LIES OVER THE US MIDWEST
AND EXTENDS NORTHWARD INTO MANITOBA AND THROUGH TO NORTHERN BAFFIN
ISLAND. AN UPPER LOW IS OVER NORTHERN QUEBEC.
AT THE SURFACE, A 994 MB LOW IS LOCATED OVER VICTORIA ISLAND WITH A
WARM FRONT SOUTHEASTWARD THROUGH WESTERN NUNAVUT AND INTO NORTHERN
MANITOBA BEFORE ARCING BACK EASTWARD AS A COLD FRONT TIED TO A 1006
MB LOW NEAR INUKJUAK. THE COLD FRONT FROM THE VICTORIA ISLAND LOW
EXTENDS SOUTHWEST INTO NORTHERN ALBERTA/BRITISH COLUMBIA AND CONNECTS
TO A 1004 MB LOW OFF THE PACIFIC NORTHWEST. A WARM FRONT IS DRAPED
ACROSS NORTH DAKOTA BOUNDING A HUMID AIRMASS OVER THE DAKOTAS.
DISCUSSION...
AB...ISOLATED SHOWERS AND NON-SEVERE THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON OVER MUCH OF SOUTHERN ALBERTA. TOMORROW AS AN UPPER LOW
CURRENTLY NEAR CORONATION MOVES NORTHWARDS TO APPROACH FORT MCMURRAY
MUCH OF THE PROVINCE COULD BECOME UNSTABLE WITH A CHANCE OF
NON-SEVERE THUNDERSTORMS.
WILDFIRE SMOKE CONTINUES TO PLAGUE SEVERAL AREAS. A WILDFIRE IN
THE RED EARTH REGION CONTINUES TO REDUCE AIR QUALITY LOCALLY.
DENSE WILDFIRE SMOKE IS NOTED OVER FIRES NEAR BUFFALO NARROWS,
SK, WHICH COULD EASILY ADVECT INTO PORTIONS OF NORTHEASTERN
ALBERTA INCLUDING FORT MACMURRAY TONIGHT. MODERATE AMOUNTS OF SMOKE
CONTINUE TO LINGER OVER WEST-CENTRAL ALBERTA, THOUGH THERE'S SOME
OPTIMISM THIS COULD CLEAR OUT BY MONDAY AS SOME WESTERLIES DEVELOP.
FINALLY, SMOKE FROM A FIRE NORTH NORTHWEST OF FORT CHIPEWYAN HAS LED
TO VERY POOR AIR QUALITY IN FORT SMITH, SO IT MAKES SENSE THAT
REGIONS DIRECTLY BORDERING THAT TOWN WOULD REQUIRE AN AIR QUALITY
WARNING.
SK/MB...AN ACTIVE CONVECTIVE PATTERN CONTINUES TODAY. SEVERAL
SHORTWAVES EMBEDDED IN THE SOUTHERLY UPPER FLOW WILL TRACK NORTHWARD
OVER THE COMING DAYS LEADING TO ROUNDS OF CONVECTIVE SHOWERS AND
EMBEDDED THUNDERSTORMS THROUGH SASKATCHEWAN AND MANITOBA. FOR TODAY'S
CONVECTIVE SET-UP, A SHORTWAVE OVER MONTANA WILL TRACK NORTHWARD
THROUGH THE DAY, SUPPORTING A BROAD AREA OF SHOWERS AND EMBEDDED
THUNDERSTORMS THROUGH EASTERN SASKATCHEWAN TODAY AND CONTINUING
THROUGH THE OVERNIGHT. THE CLOUD COVER ASSOCIATED WITH THE SHORTWAVE
AS WELL AS RESIDUAL CLOUD FROM LAST NIGHT'S OVERNIGHT CONVECTION IS
EXPECTED TO POLLUTE THE CONVECTIVE ENVIRONMENT TODAY BY LIMITING
DAYTIME HEATING AND THEREBY LIMITING CAPE VALUES AS COMPARED TO
YESETERDAY'S CONVECTIVE SETUP. GIVEN THE LIMITED CAPE, THUNDERSTORMS
THAT DEVELOP TODAY ARE EXPECTED TO BE NON-SEVERE, HOWEVER, SOUTHERLY
FLOW IS ADVECTING SEASONABLY MOIST AIR TO THE EASTERN PRAIRIES, WITH
DEWPOINTS OF 17 TO 20 DEGREES BEING ADVECTED OVER THE AREA.
PWAT VALUES OF 40+ MM IS FORECAST TO BE OVER SOUTHEASTERN
SASKATCHEWAN THIS AFTERNOON LEADING TO HEAVY RAIN CONCERNS. GIVEN THE
RICH MOISTURE AVAILABLE, HEAVY RAIN IS A CONCERN FOR TODAY AND
RAINFALL WARNINGS OR SEVERE THUNDERSTORM WARNINGS FOR HEAVY RAIN MAY
BE REQUIRED.
FIRES NEAR BUFFALO NARROWS CONTINUE TO PRODUCE SMOKE THAT HAS
RESULTED IN POOR AIR QUALITY ACROSS PARTS OF THE CENTRAL PRAIRIES.
SAQS AND AQW'S WILL CONTINUE TO BE ADJUSTED AS REQUIRED.
FOG WILL ALSO BE POSSIBLE THE NEXT FEW NIGHTS OVER THE SOUTHERN
PRAIRIES AS SEASONABLY HUMID AIR REMAINS IN PLACE OVER THE REGION.
ARCTIC...WILDFIRES LOCATED NORTHWEST OF GREAT SLAVE LAKE AND
NORTHWEST OF FORT CHIPEWYAN ARE GIVING POOR TO VERY POOR AIR
QUALITY TO FORT SMITH, YELLOWKNIFE, AND PARTS OF THE NORTH SLAVE
REGION. A DEVELOPING EASTERLY FLOW MAY CLEAR OUT THESE COMMUNITIES
IN THE NEXT 24 HOURS BUT BRING SMOKE TO OTHER COMMUNITIES IN THE
SOUTHERN NWT.
THE AMUNDSEN GULF LOW WILL BEGIN ITS TRACK EAST ACROSS THE ARCTIC
ARCHIPELAGO TODAY. RAIN ALONG THE WARM FRONT WILL MOVE THROUGH THE
KITIKMEOT. TO THE NORTH, SNOW IS EXPECTED IN RESOLUTE AND GRISE FIORD
WITH AMOUNTS IN THE 2 TO 4 CM RANGE. GRISE FIORD MAY ALSO SEE SOME
EASTERLY WINDS TODAY WITH GUSTS UP TO 70 KM/H.
THE LOW OVER VICTORIA ISLAND WILL TRACK EASTWARD THROUGH THE DAY,
WITH PRECIPITATION ASSOCIATED WITH THE LOW MOVING INTO NORTHERN
BAFFIN ISLAND AND MELVILLE PENINSULA THIS AFTERNOON. THIS SYSTEM WILL
BRING A MIX OF RAIN AND SNOW TO THE ISLAND THROUGH THE WEEKEND.
NO NOTABLE AMOUNTS ARE EXPECTED.
END/MOODIE/ZIOLKOWSKI/BATE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page