FOCN45 CWWG 031200

SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM

PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT THURSDAY JULY

3 2025.



ALERTS IN EFFECT...HEAT WARNINGS FOR PARTS OF SOUTHERN SASKATCHEWAN

AND MANITOBA, AND SOUTHEASTERN ALBERTA. AIR QUALITY STATEMENTS FOR

VARIOUS AREAS THROUGHOUT THE PRAIRIE PROVINCES.



SYNOPTIC OVERVIEW...00Z UPPER AIR ANALYSIS SHOWING AN UPPER LOW OVER

NORTHERN BC, AN UPPER RIDGE OVER THE PRAIRIE PROVINCES WITH ANOTHER

UPPER LOW OVER JAMES BAY. UPPER LOW OVER BAFFIN BAY. AT THE SURFACE,

06Z ANALYSIS SHOWING A BROAD TROUGH ALONG THE AB/SK BORDER WITH A

COLD FRONT SOUTHWEST AND A WARM FRONT SOUTHEAST. RIDGE OF HIGH

PRESSURE OVER NORTHWESTERN ONTARIO. 994 MB LOW NEAR QIKIQTARJUAQ

WITH TRAILING COLD FRONT EXTENDING SOUTHWESTWARD TO RANKIN INLET.



DISCUSSION...



AB...HEAT WARNINGS REMAIN IN EFFECT FOR PARTS OF SOUTHEASTERN

ALBERTA, TO THE SOUTH OF THE STALLED COLD FRONT, WHERE ONE MORE DAY

OF HIGH TEMPERATURES IN THE UPPER 20S/LOW 30S IS EXPECTED.



ALONG THIS FRONT, THERE EXISTS A CONDITIONAL RISK OF SEVERE

THUNDERSTORMS THIS AFTERNOON IN THE CALGARY AREA AND TO THE EAST.

LOCALIZED CONVERGENCE AND MOISTURE POOLING IN THIS AREA MAY BE

SUFFICIENT TO TRIGGER THUNDERSTORMS, PARTICULARLY ALONG THE TERRAIN

WEST OF CALGARY. IF STORMS DO FIRE IN THIS AREA, MLCAPE VALUES OF

500-1000 J/KG AND BULK SHEAR VALUES WELL IN EXCESS OF 30 KT WOULD

SUPPORT A SUPERCELL OR TWO, WITH LARGE HAIL AND STRONG WINDS BEING

THE PRIMARY THREATS.



NORTH OF THIS AREA A THUNDERSTORM RISK ALSO EXISTS FOR MUCH OF

CENTRAL AND NORTHERN ALBERTA, THOUGH WITH VERY LITTLE INSTABILITY TO

WORK WITH, THESE STORMS SHOULD BE NON-SEVERE.



ALSO IN THE FAR NORTH, WIDESPREAD SHOWERS ARE EXPECTED TODAY AND

TONIGHT ALONG A TROWAL WRAPPING BACK FROM THE LOW ALONG THE AB/SK

BORDER. RAINFALL AMOUNTS ANYWHERE FROM 20 TO 50 MM ARE EXPECTED BY

FRIDAY MORNING, THOUGH TOTALS WILL LIKELY VARY SUBSTANTIALLY ACROSS

THIS AREA WITH EMBEDDED CONVECTION.



MB/SK... SEVERE THUNDERSTORM THREAT MOVES EASTWARD TODAY AS THE BROAD

TROUGH MOVES THROUGH SK TOWARDS MB. IMPRESSIVE THERMODYNAMIC

PARAMETERS VICINITY AND EAST OF THE TROUGH, AS DEWPOINTS APPROACHING

THE 20C MARK COMBINED WITH TEMPERATURES IN THE LOW THIRTIES WILL

RESULT IN MLCAPE VALUES EXCEEDING 2500 J/KG BY LATE THIS AFTERNOON IN

AN ENVIROMENT WITH BULK SHEAR VALUES AROUND 35 KNOTS. HOWEVER,

ENVIRONMENT IS ALSO QUITE WELL CAPPED, SO THERE IS SOME QUESTION AS

TO WHETHER THE FORCING PROVIDED BY THE TROUGH WILL BE SUFFICIENT TO

TRIGGER THUNDERSTORMS THIS AFTERNOON INTO THE EARLY EVENING.

IF THUNDERSTORMS DO DEVELOP THEY ARE LIKELY TO BECOME SEVERE, WITH

LARGE HAIL, DAMAGING WINDS AND A SLIGHT TORNADIC THREAT (WHICH

SHOULD LARGELY BE CONFINED TO EXTREME SE SK AND SW MB).



MORE CONFIDENCE EXISTS FOR NOCTURNAL THUNDERSTORMS TO CONTINUE

THROUGH THE OVERNIGHT HOURS IN THE RED RIVER VALLEY AND SOUTHEASTERN

MANITOBA, AIDED BY A LOW LEVEL JET WHICH DEVELOPS THURSDAY EVENING.

DAMAGING WINDS AND LARGE HAIL WOULD BE THE MAIN THREATS.



ONGOING NOCTURNAL CONVECTION WILL COALESCE INTO A BROAD AREA

OF SHOWERS AND EMBEDDED THUNDERSTORMS ACROSS FAR NORTHERN SK TODAY

AND TONIGHT. TOTAL AMOUNTS OF GENERALLY 15 TO 30 MM ARE EXPECTED BY

FRIDAY MORNING, WITH LOCALLY HIGHER AMOUNTS IN THUNDERSTORMS

POSSIBLE.



HUMIDEX VALUES WILL HIT 40 OVER MUCH OF SOUTHERN MANITOBA OVER THE

NEXT COUPLE OF DAYS AS TEMPERATURES REACH THE LOW THIRTIES AND

DEWPOINTS APPROACH THE 20 DEGREE MARK. IN A SIMILAR VEIN, MUCH OF

SOUTHERN SASKATCHEWAN WILL SEE DAYTIME HIGHS IN THE LOW TO MID

THIRTIES, WITH HUMIDEX VALUES APPROACHING 40.



SMOKE FROM WILDFIRES WILL CONTINUE TO GIVE POOR AIR QUALITY VALUES TO

PARTS OF NORTHERN MANITOBA AND SASKATCHEWAN.



NWT...WILDFIRE SMOKE CONTINUES TO DRIFT AROUND THE SOUTHERN NWT,

THOUGH PM2.5 CONCENTRATIONS REMAIN BELOW ALERT CRITERIA.



NU...DENSE FOG IN RESOLUTE IS EXPECTED TO LIFT LATER THIS MORNING AS

WINDS SHIFT TO BE MORE OFF THE LAND.



END/FULTON/STAUNTON