214
FOCN45 CWWG 281900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT FRIDAY MARCH
28 2025.
ALERTS IN EFFECT...SNOWFALL WARNINGS FOR PORTIONS OF ALBERTA,
SASKATCHEWAN, AND MANITOBA. FREEZING DRIZZLE ADVISORY FOR PORTIONS OF
SOUTHERN SASKATCHEWAN.
SYNOPTIC OVERVIEW...ALOFT, AN UPPER LOW SITS OFF THE COAST OF
VANCOUVER ISLAND WHILE AN UPPER HIGH SITS OVER THE NORTHERN BRITISH
COLUMBIA COASTLINE WITH RIDGING NORTH THROUGH YUKON. FURTHER EAST,
MUCH OF THE EASTERN CENTRAL AND EASTERN ARCTIC IS UNDER THE INFLUENCE
OF THE CYCLONIC FLOW OF A LARGE VORTEX CENTRED WEST OF SOUTHAMPTON
ISLAND. THIS VORTEX HAS A COUPLE OF NOTABLE SHORTWAVES ROTATING
THROUGH IT, ONE OVER THE UNGAVA PENINSULA OF QUEBEC AND ANOTHER
DROPPING SOUTH THROUGH THE NUNAVUT MAINLAND OF NOTE. THE POLAR JET
DROPS SOUTH INTO THE NORTHERN PRAIRIES AND CURLS EAST WHILE THE
PACIFIC JET ENTERS NORTH AMERICAN SOUTH OF THE VANCOUVER ISLAND UPPER
LOW, LIFTS TO THE 49TH PARALLEL, THEN RUNS EAST-SOUTHEAST PARALLEL TO
THE POLAR JET ACROSS ONTARIO. A LONG-WAVE TROUGH EXTENDS FROM THE
UNGAVA SHORTWAVE SOUTHEAST OVER THE MARITIMES.
AT THE SURFACE, A 1043 MB HIGH SITS OVER THE ARCTIC OCEAN WITH A
RIDGE OF HIGH PRESSURE SOUTHEAST TO GREAT SLAVE LAKE THAT THEN CURLS
EASTWARDS ACROSS THE NORTHERN PRAIRIES INTO NW ONTARIO. EAST OF THIS,
A 1008 MB LOW SITS NEAR UNGAVA BAY WITH A WARM FRONT SOUTHEAST AND A
COLD FRONT THAT ARCS SOUTH THROUGH QUEBEC THEN CURLS WEST ACROSS NW
ONTARIO AND ALONG THE 49TH PARALLEL. THIS FRONT THEN RUNS UP THE
ALBERTA ROCKIES BEFORE CURLING NORTH THROUGH YUKON. SOUTH OF THIS, A
997 MB LOW SITS OVER EASTERN SOUTH DAKOTA WITH A COLD FRONT DRAPED
BACK SOUTHWEST AND A WARM FRONT EAST-SOUTHEAST.
DISCUSSION...
AB...SLOWLY BUT SURELY SNOW IS WINDING DOWN ALONG A DEFORMATION ZONE
CENTRED RIGHT OVER EDMONTON, BUT SIGNIFICANT SNOWFALL IS STILL
CONTINUING AT ISSUE TIME OVER THE CITY. SNOW LIQUID WATER RATIOS
WHICH APPEAR TO BE VERY HIGH AND ADDITIONAL PULSES OF MOISTURE
FEEDING IN FROM THE SOUTHWEST ARE RESPONSIBLE FOR THIS.
STORM TOTALS HAVE REACHED 33 CENTIMETRES AT WABUMUN AND SPRUCE GROVE
AND 30 CENTIMETRES AT OUR OFFICE IN EDMONTON. AT THIS POINT WE'RE
WAITING FOR SNOWFALL RATES TO DROP BEFORE FINALLY ENDING OUR
WARNINGS, PROBABLY SOMETIME THIS AFTERNOON. SEVERAL STATIONS STILL
REPORT VISIBILITY OF 1 TO 2 STATUTE MILES WHICH WOULD TRANSLATE TO
1/2 TO 1 CENTIMETRE PER HOUR OR SO, AND RADAR ECHOES ARE STILL FAIRLY
STRONG OVER TOP OF THE CITY, SO ENDING THE WARNING IS STILL NOT
WARRANTED IN SOME PLACES. BY TONIGHT WE SHOULD BE LOOKING AT LIGHTER
SNOWFALL RATES AS THE FLOW OF MOISTURE CUTS OFF AND BY SATURDAY
MOSTLY SCATTERED FLURRIES ARE EXPECTED OVER THE NORTHERN HALF OF THE
PROVINCE.
OVER THE SOUTH, WE SEE A MIX OF CONVECTIVE FLURRIES AND POCKETS OF
STRATUS AND PERHAPS OVERNIGHT AND EARLY MORNING FREEZING FOG AND
FREEZING DRIZZLE. A SHORTWAVE CROSSING THE CONTINENTAL DIVIDE WILL
CONTRIBUTE TO SCATTERED HEAVY FLURRIES.
SK/MB...SNOW WILL CONTINUE ACROSS SOUTHERN MANITOBA TODAY, SUPPORTED
BY TWO PRIMARY FEATURES OVER THE REGION. THE FIRST IS THE BROAD BAND
OF SNOW SUPPORTED BY ISENTROPIC LIFT OVER THE FRONTAL BOUNDARY DRAPED
SOUTH OF THE BORDER. LOW-LEVEL WINDS WILL GRADUALLY SHIFT TODAY AND
ISENTROPIC SUPPORT OVER THE REGION WILL WEAKEN AS THE DAY PROGRESSES.
THIS WILL RESULT IN THE HEAVY SNOW BAND WEAKENING ACROSS THE REGION
THROUGH THE DAY. SNOWFALL WARNINGS WILL BE ENDED AS THE BAND
DISSIPATES.
THE SECOND AREA OF SNOW WILL BE CONVECTIVE SNOW SHOWERS RIDING ALONG
THE UPPER JET ACROSS SE SASKATCHEWAN AND SOUTHERN MANITOBA.
ACCUMULATIONS FROM THESE SNOW SHOWERS WILL LIKELY BE LIMITED.
ELSEWHERE, MUCH OF THE REGION WILL REMAIN UNDER A DECK OF STRATUS.
LIGHT SNOW, FREEZING DRIZZLE, OR A MIX OF THE TWO WILL CONTINUE
THROUGH THE AFTERNOON HOURS IN SASKATCHEWAN. OBS AND ICE BUILD-UP ON
WEBCAMS PROMPTED THE ISSUANCE OF A FREEZING DRIZZLE ADVISORY EARLIER
THIS MORNING FOR MUCH OF THE SOUTHERN HALF OF THE PROVINCE.
THIS ADVISORY WILL REMAIN IN EFFECT INTO THE AFTERNOON AND MAY BE
EXPANDED TO PORTIONS OF WESTERN MANITOBA AS DEEMED NECESSARY.
ADDITIONAL COLD AIR ADVECTION WILL CHANGE THE FZDZ OVER TO SNOW
FRIDAY NIGHT.
CONDITIONS WILL IMPROVE SIGNIFICANTLY HEADING INTO THE AFTERNOON.
OTHERWISE, PERIODS OF LIGHT SNOW WILL TAPER OFF ACROSS THE REGION
TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE REGION THIS
WEEKEND BRINGING COOL TEMPERATURES AND QUIETER WEATHER.
ARCTIC...AS THE UNGAVA LOW CONTINUES TO DRIFT NORTH, IT WILL SPREAD
LIGHT SNOW INTO SOUTHERN BAFFIN ISLAND TONIGHT. PERIODS OF LIGHT SNOW
WILL CONTINUE THROUGH SATURDAY THEN TAPER OFF ON SUNDAY AS THE LOW
BEGINS TO DISSIPATE.
END/DYKES/VROLIJK/BATE
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