119
FOCN45 CWWG 231200
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT TUESDAY
SEPTEMBER 23 2025.
ALERTS IN EFFECT...AIR QUALITY WARNING FOR PARTS OF THE NWT NEAR
GREAT SLAVE LAKE. WIND WARNING FOR GRISE FIORD, NU. FOG ADVISORY FOR
CORAL HARBOUR AND NAUJAAT, NU. COASTAL FLOODING WARNING FOR HERSCHEL
ISLAND.
SYNOPTIC OVERVIEW...
ALOFT, AN UPPER TROUGH IS OVER THE EASTERN PACIFIC, ACCOMPANIED BY AN
UPPER LOW LOCATED OVER THE GULF OF ALASKA, ANOTHER NORTHWEST OF GREAT
SLAVE LAKE, AND ONE NEAR GJOA HAVEN. AN UPPER RIDGE EXTENDS FROM THE
WESTERN UNITED STATES NORTHEASTWARD TOWARD HUDSON BAY AND FURTHER
NORTH TOWARD GREENLAND. ADDITIONALLY, AN UPPER LOW IS PRESENT OVER
SOUTHERN GREENLAND, WITH A BROAD UPPER TROUGH EXTENDING SOUTHWARD
THROUGH QUEBEC, SOUTHEASTERN ONTARIO, AND INTO THE EASTERN UNITED
STATES.
AT THE SURFACE, A 1000 MB LOW IS LOCATED OVER THE GULF OF ALASKA,
WHILE A 996 MB LOW IS POSITIONED NORTHWEST OF GREAT SLAVE LAKE, WITH
A TROUGH EXTENDING SOUTHWARD THROUGH ALBERTA INTO WESTERN MONTANA.
A RIDGE IS EXTENDING NORTHEAST FROM A 1028 MB HIGH OVER NORTHWESTERN
WYOMING THROUGH SOUTHERN SASKATCHEWAN AND MANITOBA. LASTLY, A 985 MB
LOW IS NEAR GJOA HAVEN, AND A 1020 MB HIGH IS SITUATED NEAR JAMES
BAY.
DISCUSSION...
AB...A NARROW BAND OF PRECIPITATION WILL FORM OVER THE HINTON
REGION THIS EVENING, SPREADING EASTWARD OVERNIGHT BEFORE SHIFTING
SOUTH ON WEDNESDAY. AMOUNTS OF 10-20MM ARE EXPECTED. UNDER CLEAR
SKIES, FROST IS POSSIBLE IN HIGH LEVEL AND ALONG THE FOOTHILLS.
SK/MB...FAIRLY BENIGN WEATHER CONTINUES FOR THE REGION, SAVE FOR A
SYSTEM THAT WILL FORM OVER CENTRAL AB WEDNESDAY MORNING. THIS SYSTEM
WILL MOVE EASTWARD ACROSS THE CENTRAL AND NORTHERN PRAIRIES,
INTENSIFYING AS IT APPROACHES SOUTHERN HUDSON BAY ON WEDNESDAY NIGHT.
WHILE SCATTERED SHOWERS ARE ANTICIPATED WITH THIS SYSTEM, IT IS NOT
EXPECTED TO RESULT IN SIGNIFICANT WEATHER IMPACTS FOR THE REGION AT
THIS TIME.
IN ADDITION, ABOVE-AVERAGE SEASONAL TEMPERATURES WILL PERSIST IN THE
SOUTHERN PRAIRIES, WITH POTENTIAL FOR SCATTERED FOG PATCHES DURING
THE NIGHT AND A SLIGHT RISK OF PATCHY FROST.
NWT...MIXED PRECIPITATION CONTINUES ACROSS THE MACKENZIE DELTA THIS
MORNING BEFORE CHANGING TO RAIN SHOWERS THIS AFTERNOON. A LOW
NORTHWEST OF GREAT SLAVE LAKE IS PRODUCING RAIN SHOWERS OVER THE NWT
MAINLAND, WHICH WILL TAPER OFF AS THE SYSTEM EXITS THE REGION
TONIGHT. WILDFIRES NEAR FORT PROVIDENCE AND FORT SIMPSON CONTINUE TO
IMPACT AIR QUALITY IN THE REGION.
NUNAVUT...THE LOW SOUTHWEST OF RESOLUTE BAY CONTINUES TO GENERATE
STRONG WINDS IN GRISE FIORD, WHERE A WIND WARNING IS IN EFFECT FOR
GUSTS UP TO 90KM/H. WINDS WILL EASE THIS EVENING AS THE LOW
APPROACHES. PRECIPITATION TYPE AND AMOUNTS REMAIN UNCERTAIN WITH
TEMPERATURES HOVERING AROUND ZERO, THOUGH 5 TO 10 MM OF LIQUID
EQUIVALENT APPEARS MOST LIKELY. AS THE LOW MOVES TO THE NORTHEAST
TODAY, IT WILL BRING MIXED PRECIPITATION TO PARTS OF NORTHERN
BAFFIN ISLAND. RAIN IS ANTICIPATED TO BE THE PREDOMINANT FORM OF
PRECIPITATION IN THE COMMUNITIES, WHILE HIGHER ELEVATIONS MAY
EXPERIENCE MIXED PRECIPITATION. FOLLOWING THE PASSAGE OF THE COLD
FRONT, SCATTERED FLURRIES ARE EXPECTED TUESDAY NIGHT AND WEDNESDAY.
ADDITIONALLY, THE LOW NORTHWEST OF GREAT SLAVE LAKE WILL TRACK
EASTWARD TOWARDS THE KIVALLIQ AND SOUTHERN BAFFIN ISLAND TODAY,
BEGINNING TO AFFECT THE REGION TONIGHT AND INTO WEDNESDAY. SCATTERED
SHOWERS ARE EXPECTED TO DEVELOP OVER THE KIVALLIQ LATER THIS
AFTERNOON, INTENSIFYING AS THE SYSTEM MOVES INTO FOXE BASIN ON
WEDNESDAY MORNING. RAINFALL WILL START TO IMPACT PORTIONS OF SOUTHERN
BAFFIN ISLAND DURING THE DAY ON WEDNESDAY, WITH MIXED PRECIPITATION
LIKELY CONFINED TO HIG HER TERRAIN. AS THIS SYSTEM PROGRESSES ACROSS
DAVIS STRAIT LATER THIS WEEK, COOLER AIR WILL USHER IN ON THE
BACKSIDE, POTENTIALLY LEADING TO ACCUMULATING SNOW IN SOME
COMMUNITIES ON THE EASTERN SIDE OF THE ISLAND ADJACENT TO DAVIS
STRAIT.
OTHERWISE, WIDESPREAD FOG PERSISTS ACROSS MANY MARINE REGIONS, WITH
ONSHORE FLOW CONTRIBUTING TO FOG IN SOME COASTAL COMMUNITIES. A FOG
ADVISORY REMAINS IN EFFECT FOR CORAL HARBOUR AND NAUJAAT EARLY THIS
MORNING.
END/KOKOLSKY/GERGELY
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