FOCN45 CWWG 041900

SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM

PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT TUESDAY AUGUST

4 2026.



ALERTS IN EFFECT...RAINFALL WARNING FOR KIMMIRUT. AIR QUALITY WARNING

IN FORT SIMPSON.



OVERVIEW...ALOFT, RIDGING IS OVER WESTERN CANADA. TROUGHING THROUGH

THE HIGH ARCTIC SOUTHWARD THROUGH THE PRAIRIES WITH SEVERAL UPPER

LOWS/SHORTWAVES EMBEDDED WITHIN. MOST NOTABLY, AN UPPER LOW OVER

VICTORIA ISLAND, ANOTHER NEAR ARVIAT, ONE NEAR JAMES BAY, AND

ANOTHER OVER HUDSON STRAIT. A SHORTWAVE IS TRACKING THROUGH ALBERTA.

RIDGING IS OVER MUCH OF BAFFIN ISLAND AND DAVIS STRAIT.



AT THE SURFACE, RIDGING STRETCHES FROM THE EASTERN PACIFIC THROUGH

THE SOUTHERN PRAIRIES. A 1004 MB LOW IS OVER NWT, NEAR KUGLUKTUK. A

988 MB LOW IS OVER NUNAVUT, NEAR ARVIAT. RIDGING IS OVER BAFFIN

ISLAND.



DISCUSSION...



WESTERN PRAIRIES...A SHORTWAVE RIDING THE UPPER RIDGE WILL CONTINUE

TO DIVE SOUTH THROUGH THE DAY OWING TO NORTHERLY FLOW ALOFT.

THIS DISTURBANCE WILL KICK OFF CONTINUED CONVECTION THROUGH NORTHERN

AB AND SK TODAY. MUCH OF THE CONVECTIVE ACTIVITY WILL BE NON SEVERE

ALTHOUGH THE MOST ORGANIZED STORMS ARE LIKELY OVER NE AB BETWEEN

COLD LAKE AND FORT MCMURRAY WHERE 1000 J/KG OF MLCAPE WILL OVERLAP

WITH 20 TO 30 KTS OF BWD.



EASTERN PRAIRIES...A MUCH COOLER AND MORE STABLE DAY IS ON TAP FOR

MANITOBA UNDER A STABILIZING NORTHWEST FLOW, WHILE SOME INSTABILITY

MAY MAKE IT INTO WESTERN SASKATCHEWAN THIS AFTERNOON. SEVERE WEATHER

ISN'T EXPECTED.



THURSDAY'S THUNDERSTORM THREAT WILL MOVE INTO SOUTHERN AND CENTRAL

MANITOBA. MODEST SHEAR, ON THE ORDER OF 30 KNOTS EBWD, WILL BE IN

PLACE, SO A COUPLE OF SEVERE REPORTS OR HAIL AND WIND MAY OCCUR.



HAZY CONDITIONS WILL CONTINUE ACROSS MUCH OF THE PRAIRIES AS THE

UPPER-LEVEL FLOW SPREADS WILDFIRE SMOKE THROUGH MUCH OF THE UPPER

ATMOSPHERE OVER THE NEXT COUPLE OF DAYS. AIR QUALITY SHOULD BE MOSTLY

UNAFFECTED FOR MUCH OF THE PRAIRIES AS THE SMOKE IS EXPECTED TO

LARGELY STAY ALOFT.



NT...SOME WEAK THUNDERSTORMS ARE POSSIBLE AGAIN TODAY AND TOMORROW.



FORT SIMPSON'S AIR QUALITY DEGRADED TO THE 10+ CATEGORY AT TIMES OVER

THE LAST DAY, WITH SOME PERIODIC IMPROVEMENTS. DIFFICULT TO SAY HOW

BAD THE AIR QUALITY WILL BE HOUR TO HOUR, BUT WITH FIRES SMOLDERING

JUST OUTSIDE THE TOWNSITE THESE AQ ISSUES WILL LIKELY CONTINUE IN

THE ABSENCE OF SUBSTANTIAL RAINFALL. IN ADDITION, WITH THE NORTHERLY

FLOW IN PLACE, SMOKE IS ANTICIPATED TO MOVE INTO FORT LIARD TODAY

WHICH MAY PROMPT THE NEED FOR AN AIR QUALITY WARNING THERE AS WELL.



ALONG THE ARCTIC COAST, ONSHORE FLOW WILL BRING FOG, DRIZZLE AND

OVERCAST CONDITIONS TO THE COMMUNITIES THERE.



NU...MOISTURE WILL BE FUNNELED TOWARD KIMMIRUT OVER THE NEXT COUPLE

OF DAYS AHEAD OF THE NWT/NU TROUGH. GUIDANCE IS IN GOOD AGREEMENT

THAT RAINFALL, ESPECIALLY TONIGHT AND WEDNESDAY MORNING, WILL BE

FAIRLY STEADY AND WILL ACCUMULATE ENOUGH TO WARRANT A BULLETIN.

A RAINFALL WARNING HAS BEEN ISSUED HERE, AS 30-50 MM OF STORM TOTAL

IS LIKELY. OTHERWISE THE EASTERN ARCTIC WILL BE FAIRLY BENIGN THIS

FORECAST PERIOD.



END/CARLSEN/MOODIE/VAN LOCHEM/GREENHOUGH