865
FOCN45 CWWG 071900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT FRIDAY AUGUST
7 2026.
ALERTS IN EFFECT...AIR QUALITY WARNINGS IN FORT SIMPSON AND PARTS OF
ALBERTA.
OVERVIEW...ALOFT TODAY, THE FLOW IS DOMINATED BY A LARGE VORTEX
ANCHORED OVER WESTERN HUDSON BAY. IT HAS 3 PROMINENT SHORTWAVES
ROTATING THROUGH IT: ONE OVER NORTHWEST MANITOBA, ANOTHER LIFTING
INTO SOUTHERN HUDSON BAY, AND A THIRD OVER CENTRAL HUDSON BAY. TO THE
WEST OF THIS, A WEAK UPPER RIDGE SITS OVER WESTERN CANADA WITH APEX
RUNNING FROM IDAHO NORTH-NORTHWEST ALONG THE ROCKIES TO CENTRAL
BRITISH COLUMBIA. A COMPACT AND DRY SHORTWAVE IS VISIBLE NORTH OF
THIS OVER NW ALBERTA. TO THE EAST, A WEAK UPPER RIDGE EXTENDS NORTH
THROUGH QUEBEC WITH A DOWNSTREAM SHORTWAVE OVER LABRADOR. IN THE
NORTH, AN UPPER LOW SITS OVER NORTHERN ALASKA, WHILE A BROAD UPPER
HIGH SPRAWLS OF MUCH OF THE REST OF THE ARCTIC WITH CENTRES OVER
BANKS ISLAND AND BAFFIN BAY.
AT THE SURFACE, A 999 MB LOW SITS OVER CENTRAL HUDSON BAY WITH AN
OCCLUDED FRONTAL WAVE ITS EAST NEAR THE QUEBEC COAST; A COLD FRONT
SWEEPS SOUTHWEST THROUGH NW ONTARIO INTO THE UNITED STATES WHILE A
WARM FRONT IS DRAPED EAST INTO QUEBEC. A TROUGH OF LOW PRESSURE
EXTENDS WEST FROM THIS LOW ACROSS THE NORTHERN PRAIRIES. WEST OF
THIS, A 1019 MB HIGH SITS OVER NW NORTH DAKOTA WITH RIDGING THAT
EXTENDS NORTHWEST ACROSS SASKATCHEWAN INTO NORTHERN ALBERTA. IN THE
NORTH, A BROAD AREA OF HIGH PRESSURE IS DRAPED ACROSS THE CANADIAN
ARCTIC ARCHIPELAGO WITH RIDING SOUTH INTO THE NORTHWEST TERRITORIES
AND EAST TO A 1031 MB HIGH OVER GREENLAND.
DISCUSSION...
WESTERN PRAIRIES...THE MAIN FOCUS FOR TODAY WILL BE THE SMOKE
DRIFTING BOTH SOUTHWARD FROM THE NT AND EASTWARD FROM BC.
THE HEAVIEST CONCENTRATION OF PM 2.5 VALUES SHOULD REMAIN CLOSE TO
THE MOUNTAIN PARKS AND OVER NORTHWESTERN AB. AQHI VALUES HAVE
REMAINED MOSTLY IN THE MODERATE RANGE SO FAR THIS MORNING. CONDITIONS
IN WESTERN AND POSSIBLY SOUTHERN ALBERTA ARE EXPECTED TO WORSEN THIS
AFTERNOON, PARTICULARLY IN THE MOUNTAIN PARKS, BUT THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST SMOKE WILL BE ABLE TO REACH THE
SURFACE AWAY FROM THE TERRAIN. THE SITUATION WILL BE MONITORED
CLOSELY AND WARNINGS WILL BE EXPANDED AS REQUIRED.
THUNDERSTORMS ARE ALSO POSSIBLE AGAIN TODAY AND TONIGHT OVER
WEST-CENTRAL REGIONS AS A SHORTWAVE TROUGH MAKES ITS WAY THROUGH THE
NORTHERN ROCKIES TOWARDS THE CAPITAL REGION AND BEYOND. THUNDERSTORMS
ARE EXPECTED TO REMAIN SUB-SEVERE.
FOG PATCHES ARE POSSIBLE TONIGHT OVER NORTHERN ALBERTA.
EASTERN PRAIRIES...SCATTERED THUNDERSHOWERS WILL DEVELOP OVER
PORTIONS OF NORTHERN AND CENTRAL MANITOBA THIS AFTERNOON AS DAYTIME
HEATING PRODUCES A COUPLE OF HUNDRED J/KG OF SBCAPE. BULK SHEAR IS 15
KNOTS OR LESS. NO SEVERE WEATHER IS EXPECTED. A FEW NON-SUPERCELL
FUNNEL CLOUDS WILL BE POSSIBLE TODAY WITH THE COOLER TEMPERATURES,
STRONG INSOLATION, AND HIGH VORTICITY ENVIRONMENT AS A SHORTWAVE
TRACKS ACROSS NORTHERN MANITOBA.
LITTLE CHANGE OVER THE COMING DAYS AS A NORTHWEST FLOW CONTINUES OVER
NORTHERN MANITOBA.
AN INCREASING AMOUNT OF SMOKE ALOFT WILL SPREAD ACROSS SOUTHERN
SASKATCHEWAN INTO SOUTHWEST MANITOBA OVER THE COMING DAYS, BUT THE
NEAR-SURFACE IMPACT IS EXPECTED TO BE MINIMAL. SOME DETERIORATION IN
AIR QUALITY WILL BE POSSIBLE IN THE COMING DAYS OVER FAR SOUTHWESTERN
SASKATCHEWAN, OTHERWISE HAZY SKIES WILL BE THE PRIMARY IMPACT FOR THE
REST OF THE REGIONS IN THE PATH OF THE SMOKE PLUME.
NT...AN AIR QUALITY WARNING REMAINS IN EFFECT FOR THE FORT SIMPSON
REGION, WHERE CONDITIONS HAVE PERIODICALLY BEEN QUITE POOR DUE TO
FOREST FIRES UPWIND OF THE COMMUNITY.
NU...RAIN SHOWERS WILL CONTINUE TO ROTATE AROUND THE HUDSON BAY UPPER
LOW OVER THE COMING DAYS. SOME AREAS ALONG THE HUDSON BAY COAST COULD
SEE AS MUCH AS 10 TO 15 MM OF RAIN BY SATURDAY EVENING, BUT BROADLY
ACCUMULATIONS WILL BE LESS THAN THAT.
ON SATURDAY, MODERATE WINDS WILL DEVELOP OUT OF HUDSON STRAIT AND
ACROSS SOUTHAMPTON ISLAND AND TO THE KIVALLIQ COAST. WIND GUSTS OF 50
TO 70 KM/H WILL BE POSSIBLE LATER SATURDAY AND INTO SUNDAY BEFORE THE
WINDS DIMINISH. MODERATE WINDS WILL PERSIST A BIT LONGER OVER HUDSON
STRAIT AND INTO KINNGAIT (CYTE), NOT EASING UNTIL MONDAY.
IN ADDITION TO THE RAIN SHOWERS, RELATIVELY MILD AIR BEING PUMPED
OVER THE COOLER WATERS OF HUDSON BAY HAS RESULTED IN BROAD AREAS OF
FOG ACROSS THE REGION STUCK BELOW THE MARINE INVERSION. FOG PATCHES
WILL BE COMMONPLACE ACROSS HUDSON BAY AND THE ADJACENT COASTAL
COMMUNITIES INTO THE WEEKEND.
END/VROLIJK/STAUNTON
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