876
FOCN45 CWWG 281900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT SUNDAY JUNE
28 2026.
ALERTS IN EFFECT...RAINFALL WARNING FOR MOST OF SOUTHERN AND CENTRAL
ALBERTA. HEAT WARNINGS FOR PARTS OF THE NORTHWEST TERRITORIES,
NORTHERN ALBERTA, NORTHERN SASKATCHEWAN, KUGAARUK AND CORAL HARBOUR.
AIR QUALITY WARNING FOR NORMAN WELLS AND HAY RIVER.
OVERVIEW...ALOFT, A DIGGING UPPER TROUGH EXTENDS FROM AN UPPER LOW
OFF THE WESTERN COAST OF ALASKA, ALONG THE BC COAST, AND INTO THE
NORTHWESTERN US STATES. AN UPPER LOW SITS IN THE BASE OF THE TROUGH,
OVER OREGON. ANOTHER UPPER LOW IS LOCATED WITHIN THE TROUGH, OVER
SOUTHERN SASKATCHEWAN. SEVERAL SHORTWAVES ARE EMBEDDED WITHIN THE
TROUGH. A STRONG SOUTHWESTERLY JET IS POKING INTO SOUTHEASTERN
SASKATCHEWAN AND SOUTHWESTERN MANITOBA. AN UPPER RIDGE EXTENDS FROM
THE AMERICAN MIDWEST TO THE NORTHWEST, CUTTING ACROSS SOUTHERN
MANITOBA, SASKATCHEWAN, AND NORTHERN ALBERTA TO AN UPPER HIGH
SITUATED OVER THE NORTHWEST TERRITORIES. RIDGING CONTINUES FROM THIS
HIGH WEST ACROSS YUKON AND ALASKA. A STRONG JET CUTS ACROSS THE HIGH
ARCTIC WITH AN UPPER LOW OVER THE ARCTIC OCEAN, A DOWNSTREAM RIDGE
OVER THE EASTERN CANADIAN ARCTIC ARCHIPELAGO, AND ANOTHER UPPER LOW
OVER GREENLAND.
AT THE SURFACE, RIDGING DOMINATES THE EASTERN PACIFIC. AN OCCLUDED
996 MB LOW IS OVER SOUTHEASTERN SASKATCHEWAN WITH A TROUGH EXTENDING
NORTHWESTWARD THROUGH TO ALASKA. WEAK LOW PRESSURE CENTERS ARE
LOCATED ALONG THE TROUGH. HIGH PRESSURE IS OVER HUDSON BAY WITH A
RIDGE THAT EXTENDS INTO KIVALLIQ AND SOUTHERN BAFFIN ISLAND.
DISCUSSION...
AB/NRN SK...THERE IS A LOT GOING ON OVER THE AOR: THUNDERSTORMS,
HEAVY RAIN, HEAT, AND SMOKE.
STARTING WITH THUNDERSTORMS, WE HAVE TWO MAIN AREAS OF THUNDERSTORM
POTENTIAL TODAY; ONE OVER SOUTHERN ALBERTA AND ANOTHER OVER THE
NORTHWEST.
IN SOUTHERN ALBERTA, THUNDERSTORMS WILL BE FOCUSED NEAR THE LOW AND
ALONG THE TROUGH TO THE NORTH. OVER THE SOUTH, THUNDERSTORMS WILL
PRIMARILY BE FOCUSED AROUND THE LOW THAT IS RETROGRADING TO THE WEST
THROUGH SOUTHERN ALBERTA. THESE STORMS WILL BE NON-SEVERE AND PRIMARY
ACT TO ENHANCE THE PRECIPITATION TOTALS AROUND THE LOW PRESSURE
CENTRE. IN ADDITION NEAR THE LOW, CONDITIONS WILL BE FAVOURABLE FOR
THE DEVELOPMENT OF FUNNEL CLOUDS PROVIDED THERE IS ENOUGH CLEARING
WHICH CAN ALLOW CONVECTIVE CELLS TO DEVELOP.
IN THE NORTHWEST, ALONG THE SURFACE TROUGH, DEWPOINT VALUES WILL BE
ELEVATED IN THE SOUTHEASTERLY FLOW. WITH FORECAST HIGHS BEING IN THE
MID TO HIGH 20'S AND DEWPOINTS IN THE MID TEENS, MODERATE SBCAPE
VALUES OF 1700-2000 J/KG WILL BE ENOUGH TO SEE A FEW STORMS DEVELOP
HOWEVER, SHEAR IS WEAK SO THE ABILITY TO SEE LONG LIVED STORMS WILL
BE LIMITED. PRIMARY THREATS WOULD BE HEAVY RAIN, AND SMALL HAIL.
RAINFALL WARNINGS REMAIN IN EFFECT FOR MUCH OF ALBERTA AND WARNINGS
THAT HAVE BEEN EXPANDED TO THE REST OF THE SOUTH. A STRONG REX BLOCK
IS IN PLAY WITH THE SURFACE LOW FIRMLY IN PLACE OVER SOUTHERN
SASKATCHEWAN. THE LOW WILL CONTINUE TO RETROGRADE TO THE WEST TODAY,
PUSHING THE PRECIPITATION INTO THE FOOTHILLS REGIONS. WITH EMBEDDED
CONVECTION CONTINUING AROUND THE LOW, RAINFALL TOTALS ARE EXPECTED TO
BE SOMEWHAT VARIABLE WITH ENHANCED AMOUNTS ALONG THE TERRAIN AND IN
THE CONVECTION. IN GENERAL, THE HIGHEST PRECIPITATION IS EXPECTED TO
BE NEAR OR EXCEEDING 100MM IN THE WESTERN UPSLOPE REGIONS. IN THE
SOUTHEAST, ANY BREAKS IN THE RAINFALL ARE LIKELY TO FILL IN WITH
CONVECTION AND THUNDERSTORM ACTIVITY AND THUS DRIVE UP PRECIPITATION
TOTALS IN THESE AREAS. IN ADDITION, CONVECTION THAT DEVELOPS OVER
SASKATCHEWAN WILL THEN TRACK WESTWARD AND FEED INTO THE LOW,
REFRESHING THE SUPPLY OF MOISTURE AND DRIVING UP RAINFALL TOTALS.
THE HEAVIEST RAIN WILL FALL TODAY AND TONIGHT AND SLOWLY TAPER OFF
MONDAY NIGHT.
HEAT WARNINGS REMAIN IN EFFECT OVER EXTREME NORTHERN ALBERTA, AND
NORTHERN SASKATCHEWAN AS WELL, WITH SOME EXPANSION OF THE
WARNINGS TO NORTHWESTERN SASKATCHEWAN. A FEW PLACES IN NORTHERN
ALBERTA WILL BE NEAR CRITERIA, BUT OVERNIGHT LOWS LOOK TO STAY
COOL ENOUGH TO PREVENT HITTING WARNING CRITERIA. THIS HEAT WILL
CONTINUE THROUGH EARLY TO MID THIS WEEK.
A FIRE IN THE PELICAN NARROWS REGION IS GENERATING LOCALIZED SMOKE
FOR THE FORECAST REGION. FIRES HAVE ALSO BEEN DETECTED IN THE KEY
LAKE REGION AS WELL AS SOUTH OF STONY RAPIDS. LOCAL SMOKE MAY AFFECT
THE FORECAST SITES AT TIMES AS THE WINDS SHIFT, AND WITH A STRONGER
EASTERLY WIND DEVELOPING OVER THE NEXT COUPLE OF DAYS, WE WILL
LIKELY SEE THE SMOKE MOVE WESTWARD AND INTO NORTHEASTERN ALBERTA.
ALERTS WILL BE ISSUED AS REQUIRED.
SK/MB...SIGNIFICANT SEVERE WEATHER POTENTIAL CONTINUES SUNDAY FOR
PARTS OF SASKATCHEWAN AND MANITOBA. AMPLE HEAT AND HUMIDITY
CONTINUES TO BE ADVECTED NORTHWARD IN PERSISTENT SOUTHERLY FLOW WITH
FAVOURABLE UPPER DYNAMICS SUPPORTING A MULTI-DAY SEVERE WEATHER
SETUP THAT WILL CONTINUE INTO NEXT WEEK.
FOR SUNDAY'S SEVERE THUNDERSTORM SETUP, THE MAIN AREA OF CONCERN
IS OVER EASTERN SASKATCHEWAN AND WESTERN MANITOBA. THE UPPER LOW
OVER SOUTHERN SASKATCHEWAN WILL SLOWLY RETROGRADE WESTWARD THROUGH
THE DAY WITH A STRONG SOUTHWESTERLY JET MOVING INTO SOUTHEASTERN
SASKATCHEWAN AND SOUTHWESTERN MANITOBA. THE LEFT EXIT REGION OF THE
MAIN JET CORE IS PROGGED TO BE OVER SOUTHWESTERN MANITOBA BY LATE
THIS AFTERNOON. BULK SHEAR VALUES OF 40 TO 50 KTS ARE EXPECTED OVER
THE REGION BY 21Z. WITH THE PERSISTENT SOUTHERLY FLOW CONTINUING TO
PUMP HEAT AND MOISTURE NORTHWARD, DAYTIME HIGHS ARE FORECAST TO BE
IN THE MID TWENTIES, AND DEWPOINTS ARE PROGGED TO BE IN THE MID TO
HIGH TEENS WITH MLCAPE VALUES OF 1000 TO 1500 J/KG EXPECTED TO BE
OVER THE AREA. WITH THE EXPECTED CAPE VALUES TODAY, AND AMPLE SHEAR,
STRONG WIND AND LARGE HAIL ARE NOTABLE SEVERE WEATHER THREATS. AND,
WITH THE PERSISTENT TRANSPORT OF MOISTURE NORTHWARD, HIGH PWAT
VALUES OF 35 TO 45 MM ARE LEADING TO HEAVY RAINFALL CONCERNS OVER
ALREADY MOIST AREAS. LATEST SATELLITE TRENDS HAVE SHOWN AMPLE
CLEARING OVER SOUTHWESTERN MANITOBA WITH AN AREA OF LOW LEVEL
MOISTURE SURGING NORTHWEST TOWARDS THE PARKLANDS REGION OF MANITOBA.
THE FOCUS FOR SEVERE CONVECTION WILL BE THE FRONTAL WAVE ASSOCIATED
WITH THE OCCLUDED SURFACE LOW, PROGGED TO BE OVER SOUTHWESTERN
SASKATCHEWAN BY THE AFTERNOON. THE APEX OF THE ASSOCIATED FRONTAL
WAVE IS FORECAST TO BE OVER EAST-CENTRAL SASKATCHEWAN WITH THE COLD
FRONT SOUTHWARD INTO THE WESTERN DAKOTAS. THE WARM FRONT IS PROGGED
TO EXTEND SOUTHEASTWARD THROUGH SOUTHERN MANITOBA. DECENT
DIRECTIONAL SHEAR WILL BE IN THE WARM SECTOR AND VICINITY OF THE
WARM FRONT, WITH SOUTHEASTERLY SURFACE FLOW, AND LOW LCLS EXPECTED
DUE TO AMPLE SURFACE MOISTURE, WILL LEAD TO A RISK OF TORNADOES IN
THUNDERSTORMS THAT FORM IN THIS AREA. GIVEN THE SUBSTANTIAL DYNAMIC
SUPPORT, THUNDERSTORMS THAT INITIATE ARE EXPECTED TO PERSIST THROUGH
THE OVERNIGHT AS THEY TRACK EASTWARD.
FURTHER WEST, WITH THE UPPER LOW SITTING OVER SOUTHWESTERN
SASKATCHEWAN AND MULTIPLE SHORTWAVES IN THE AREA, THE ENVIRONMENT
OVER SOUTHERN SASKATCHEWAN WILL LIKELY BE FAVOURABLE FOR THE
DEVELOPMENT OF FUNNEL CLOUDS IS POSSIBLE WITH CONVECTION THAT
DEVELOPS ALONG THE SURFACE TROUGH SITUATED OVER THE KINDERSLEY
REGION.
ALONG THE OCCLUSION/TROWAL ASSOCIATED WITH THE LOW OVER SOUTHWESTERN
SASKATCHEWAN, ANOTHER CONCERN IS HEAVY CONVECTIVE RAINFALL OVER
CENTRAL AND WESTERN SASKATCHEWAN. AMOUNTS WILL BE VERY HARD TO NAIL
DOWN WITH EMBEDDED CONVECTION LEADING TO LOCALIZED HEAVY RAINFALL
AMOUNTS, BUT 30 TO 40 MM OF RAINFALL IS LIKELY IN THIS REGION, WITH
HIGHER AMOUNTS POSSIBLE IN EMBEDDED HEAVIER CONVECTION. GIVEN THE
OVERLAND FLOODING VULNERABILITIES OF SOME OF THESE AREAS, THIS
SITUATION WILL BE MONITORED AND A RAINFALL WARNING MAY BE REQUIRED
IF A HEAVY BAND OF RAINFALL SETS UP OVER AN AREA.
IN NORTHERN MANITOBA, SCATTERED AIR-MASS THUNDERSTORMS ARE POSSIBLE
AGAIN THIS AFTERNOON AS A WEAK UPPER LOW/UPPER TROUGH CONTINUES TO
SIT OVER THE REGION.
ALSO OF NOTE, WITH HEAT AND HUMIDITY ON THE RISE ACROSS SOUTHERN
MANITOBA INTO NEXT WEEK, HEAT WARNINGS MAY BE REQUIRED BY MID TO
LATE WEEK TO START OFF JULY.
IN NORTHERN MANITOBA, WILDFIRE SMOKE WILL CONTINUE TO PROPAGATE
THROUGH MUCH OF THE REGION, GRADUALLY SHIFTING TO BE A CONCERN FOR A
COUPLE AREAS ALONG THE SASKATCHEWAN BORDER AS AN EASTERLY FLOW
DEVELOPS -- MAINLY PARTS OF THE THOMPSON, LYNN LAKE, AND FLIN FLON
REGIONS.
NUNAVUT...ABOVE SEASONAL TEMPERATURES WILL CONTINUE WELL INTO NEXT
WEEK WITH CORAL HARBOUR SEEING HEAT WARNING LEVEL CRITERIA. DESPITE
SEEING TEMPERATURES WELL ABOVE SEASONAL, OTHER SITES ACROSS THE
KIVALLIQ AND SOUTHERN BAFFIN ISLAND LOOK TO REMAIN BELOW HEAT WARNING
LEVEL THRESHOLDS. TEMPERATURES IN THE KITIKMEOT ARE AT ALERT
CRITERIA WITH DAYTIME HIGHS AT OR ABOVE 22C. CONDITIONS SHOULD
IMPROVE OVERNIGHT TONIGHT.
MORE SHOWERS AND THUNDERSHOWERS WILL DEVELOP ALONG THE WEST SIDE OF
THE UPPER HIGH OVER THE KIVALLIQ MAINLAND AND EASTERN NWT FOR THE
NEXT FEW DAYS. THERE WILL BE ONLY 10 TO 15 KNOTS OF 0-6 KM BULK
SHEAR, SO EXPECTING PULSE THUNDERSHOWERS WITH SOME HEAVIER RAIN.
NWT...VERY WARM TEMPERATURES CONTINUE OVER MUCH OF THE TERRITORY.
FROM FORT GOOD HOPE SOUTHWARD THROUGH THE MACKENZIE VALLEY TO
REGIONS AROUND GREAT SLAVE LAKE WHERE HEAT WARNINGS REMAIN IN EFFECT
AS DAYTIME HIGHS BETWEEN 29-33 DEGREES CELSIUS ARE FORECAST INTO
EARLY THIS WEEK. TEMPERATURES WILL SLOWLY MODERATE FROM NORTH TO
SOUTH OVER THE NEXT FEW DAYS AS SOME COOLER AIR SLOWLY MOVES IN FROM
THE NORTHWEST.
WILDFIRE SMOKE CONTINUES TO INTERMITTENTLY IMPACT THE NORMAN WELLS
REGION, PARTICULARLY IN THE OVERNIGHT/EARLY MORNING HOURS. AN AIR
QUALITY WARNING REMAINS IN EFFECT. AN AIR QUALITY WARNING WAS ALSO
BEEN ISSUED FOR HAY RIVER. EASTERLY WINDS WILL RETURN TODAY AND ARE
EXPECTED TO BRING SMOKE BACK INTO THE REGION FROM A FIRE WEST OF
FORT SMITH.
SCATTERED THUNDERSTORMS ARE EXPECTED AGAIN TODAY ACROSS MAINLY THE
WESTERN SECTIONS OF THE TERRITORY. GIVEN THE AMPLE MLCAPE VALUES AND
TD'S, MEAGRE SHEAR, AND SIMILAR TRIGGERS TO YESTERDAY, MOST (IF NOT
ALL) STORMS SHOULD REMAIN SUB-SEVERE IN NATURE. THERE IS A VERY
SLIGHT CHANCE OF A STORM BECOMING MORE SEVERE ALONG THE TERRAIN TO
THE WEST/NEAR OF NORMAN WELLS HOWEVER, THERE MAY NOT BE ENOUGH SHEAR
TO SUPPORT STRONGER STORMS. NOTHING ORGANIZED IS ANTICIPATED.
IN THE DELTA, A WEAK LOW WILL MOVE THROUGH THE AREA AND BRING SOME
RAIN TODAY AND TONIGHT. RAINFALL TOTALS WILL BE NEAR 25 MM IN A FEW
LOCATIONS.
END/MOODIE/ZIOLKOWSKI/GREENHOUGH/VAN LOCHEM
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