FOCN45 CWWG 211200

SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM

PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT MONDAY

SEPTEMBER 21 2026.



ALERTS IN EFFECT...STORM SURGE WARNING FOR HERSCHEL ISLAND.

FOG ADVISORY FOR CAMBRIDGE BAY.



SYNOPTIC OVERVIEW...ALOFT, A LONGWAVE TROUGH SITS OVER THE PACIFIC.

A BROAD UPPER RIDGE SPRAWLS OVER WESTERN CANADA WITH THE RIDGE AXIS

OVER MANITOBA AND UP INTO NUNAVUT. AN UPPER TROUGH IS EMBEDDED IN THE

FLOW NEAR THE NWT/NUNAVUT BORDER. TWO SHORTWAVES ARE ALSO EMBEDDED

NEAR THE RIDGE AXIS: ONE JUST WEST OF SOUTHAMPTON ISLAND AND THE

OTHER NEAR THE ONTARIO/HUDSON BAY COAST. AN UPPER LOW IS NEAR THE

QUEBEC/LABRADOR BORDER WITH TROUGHING SOUTHWARDS.



AT THE SURFACE, A WEAK RIDGE IS OVER BC AND YUKON. A LOW NORTH OF

GREAT BEAR LAKE HAS A TROUGH EXTENDING SOUTH INTO ALBERTA. ANOTHER

LOW NEAR PRINCE OF WHALES ISLAND HAS A WARM FRONT DRAPPING SOUTH

TROUGH MAINLAND NUNAVUT AND WESTERN HUDSON BAY. A HIGH PRESSURE

CENTRE SITS JUST NORTH OF LAKE SUPERIOR WITH A RIDGE EXTENDING NORTH

INTO EASTERN HUDSON BAY AND BAFFIN ISLAND. FINALLY, A LOW IS NEAR THE

QUEBEC/LABRADOR BORDER.



DISCUSSION...



WESTERN PRAIRIES...ONCE AGAIN, THINGS REMAIN QUIET AS A BROAD UPPER

RIDGE MAINTAINS ITSELF OVER THE PRAIRIES. SOME MINOR FROST RISKS

TONIGHT IN A FEW COMMUNITIES, ESPECIALLY THOSE NEAR THE FOOTHILLS.

ISOLATED SHOWERS AND PERHAPS A LIGHTNING STRIKE OR TWO ARE ALSO

POSSIBLE WITH A WEAK COLD FRONT THIS EVENING OVER PARTS OF NORTHERN

ALBERTA.



EASTERN PRAIRIES...PATCHY FOG HAS FORMED OVERNIGHT IN SOUTHERN

SASKATCHEWAN AND MANITOBA. THIS FOG WILL DISSIPATE LATER THIS

MORNING.



WITH THE UPPER RIDGE OVER THE AREA, WEATHER WILL BE QUIET FOR THE

EARLY PART OF THIS WEEK. ONE THING OF NOTE IS THE SOUTHERLY WINDS AT

THE SURFACE WHICH WILL BRING WARM AIR TO THE AREA. DAYTIME HIGHS ARE

EXPECTED TO BE 5 TO 10 DEGREES ABOVE NORMAL FOR THE MAJORITY OF THE

WEEK.



WESTERN ARCTIC...MAIN FEATURE OF NOTE IS A DEVELOPING LOW PRESSURE

SYSTEM ALONG THE ARCTIC COAST. THIS SYSTEM WILL BRING SOME RAIN

SHOWERS TO THE COASTAL NWT AND THE KITIKMEOT TODAY AND TONIGHT, WITH

5-10 MM OF RAIN EXPECTED. THERE IS ALSO A VERY SLIGHT CHANCE OF A

LIGHTNING STRIKE OR TWO IN THE AREA WITH THIS SYSTEM.



A FOG ADVISORY HAS BEEN ISSUED FOR CAMBRIDGE BAY. CONDITIONS ARE

EXPECTED TO IMPROVE THIS MORNING AS WINDS SHIFT TO BLOW MORE

OFFSHORE.



A STORM SURGE WARNING CONTINUES FOR HERSCHEL ISLAND. MODERATE

FLOODING IS EXPECTED AT HIGH TIDE LATE THIS MORNING/EARLY THIS

AFTERNOON. A BRIEF REPREIEVE IS POSSIBLE TONIGHT, BUT MINOR TO

MODERATE FLOODING IS EXPECTED AGAIN TUESDAY/WEDNESDAY.



EASTERN ARCTIC...THE WARM FRONT FROM THE PRINCE OF WHALES ISLAND LOW

WILL BRING AN AREA OF SHOWERS TO NORTHERN BAFFIN ISLAND, MELVILLE

PENINSULA, AND SOUTHAMPTON ISLAND TODAY AND TONIGHT. THE SHOWERS WILL

BE MIXED WITH SNOW AT TIMES, FOR THE COMMUNITIES ON NORTHERN BAFFIN

ISLAND. A SECOND WAVE OF SHOWERS WILL IMPACT THE SAME AREAS, AS THE

LOW NORTH OF GREAT BEAR LAKE ENTERS THE REGION OVERNIGHT MONDAY AND

INTO TUESDAY. TOTAL ACCUMULATIONS FROM BOTH SYSTEMS ARE NOT EXPECTED

TO BE SIGNIFICANT FOR MOST COMMUNITIES. HIGHEST ACCUMULATIONS WILL BE

OVER NORTHERN BAFFIN WITH 10 TO 20 MM POSSIBLE BY WEDNESDAY.



HIGH ARCTIC...THE LOW ALONG THE ARCTIC COAST WILL MAKE ITS WAY

STEADILY NORTHEASTWARD, BRINGING STRONG WINDS TO THE HIGH ARCTIC ON

TUESDAY.



END/BILOUS/STAUNTON