730
FOCN45 CWWG 181200
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT FRIDAY APRIL
18 2025.
ALERTS IN EFFECT...BLIZZARD WARNING FOR GJOA HAVEN AND RESOLUTE.
SNOWFALL WARNING FOR SOUTH DELTA AND CAMBRIDGE BAY.
SYNOPTIC OVERVIEW...ALOFT, AN UPPER RIDGE RUNS FROM THE EASTERN
PACIFIC THROUGH BC AND INTO THE SOUTHERN NWT. AN UPPER LOW IS OVER
CENTRAL SASKATCHEWAN AND MANITOBA WITH A DIGGING TROUGH EXTENDING
SOUTHWESTWARD. AN UPPER RIDGE IS OVER ONTARIO. AN UPPER LOW IS OVER
NORTHERN BAFFIN BAY WITH A TROUGH SOUTHEASTWARD TO ANOTHER LOW OVER
SOUTHERN LABRADOR.
AT THE SURFACE, THE LOW PREVIOUSLY OVER MB HAS OCCLUDED INTO A
HANGBACK TROUGH FROM A 1003MB LOW OVER NORTHERN WISCONSIN. A 996 MB
LOW LIES WEST OF FORT GOOD HOPE. A RIDGE OF HIGH PRESSURE EXTENDS
SOUTHWESTWARD FROM THE SOUTHERN KIVALLIQ INTO NORTHERN SASKATCHEWAN.
A 990 MB LOW IS OVER LABRADOR.
DISCUSSION...
AB...A COLD FRONT WILL BEGIN TO SWEEP THROUGH ALBERTA
TONIGHT, BRINGING SHOWERS TO NORTHERN PARTS OF THE PROVINCE. IT WILL
PROGRESS INTO CENTRAL AND SOUTHERN ALBERTA SATURDAY, AGAIN CARRYING
SHOWERS ALONG WITH IT. THESE REGIONS WILL LIKELY SEE SOME MORE
ORGANIZED SHOWERS ALONG THE FRONT, WITH 5-10MM EXPECTED FOR SOME
PARTS OF CENTRAL ALBERTA. SHOWERS WILL ALSO CLIP THE ROCKIES LATE
TONIGHT AND SATURDAY, WITH HIGHER ELEVATIONS LIKELY SEEING FLURRIES.
FINALLY, THERE IS ALSO A VERY SLIGHT CHANCE OF A LIGHTNING STRIKE OR
TWO ALONG THE FOOTHILLS SATURDAY AFTERNOON WITH THIS SHOWER ACTIVITY.
SK/MB...THE SLOWLY TRUNDLING UPPER LOW WILL CONTINUE TO EXIT THE
REGION INTO NORTHERN ONTARIO. BETWEEN THE EXITING SYSTEM AND THE
BUILDING HIGH PRESSURE FROM THE WEST, GENERAL NORTHWESTERLY FLOW OVER
SOUTHEASTERN SK AND SOUTHERN MB WILL SEE SHOWERS AND FLURRIES
CONTINUE THIS MORNING OVER THE AREA. AREAS EAST OF LAKE WINNIPEG MAY
SEE SOME ENHANCED SNOWFALL AS A TIGHTLY WRAPPED MID-LEVEL VORTEX
PHASES TOGETHER WITH A HANGBACK SURFACE TROUGH FROM A LOW THAT IS
PASSING THROUGH MINNESOTA INTO ONTARIO. ALTHOUGH THERE WILL BE STRONG
FORCING, INSTABILITY IS MEAGRE, ALONG WITH LESS THAN FAVOURABLE SNOW
GROWTH PROFILES, AND ACCUMULATIONS WILL BE LIMITED. ALL FLURRIES
SHOULD DIMINISH BY THE EVENING ON FRIDAY.
HIGH PRESSURE WILL DOMINATE ON FRIDAY NIGHT INTO SATURDAY.
LATE SATURDAY EVENING, AN ARCTIC LOW MOVING INTO THE KIVALLIQ REGION
WILL DRAPE A FRONTAL WAVE OVER THE PRAIRIES THAT WILL INTRODUCE SOME
SCATTERED SHOWERS AND FLURRIES TO NORTHERN MANITOBA AND SASKATCHEWAN.
NWT...THE DEVELOPING LOW IN THE NORTHERN NWT WILL BRING A BAND OF
HEAVY SNOW FROM FORT MCPHERSON ACROSS GREAT BEAR LAKE TODAY. 10 TO
15 CM IS EXPECTED FOR FORT MCPHERSON AND TSIIGEHTCHIC TODAY BEFORE
THE SNOW TAPERS OFF THIS EVENING. COLVILLE LAKE WILL ALSO NEED TO BE
MONITORED FOR HEAVY SNOW POTENTIAL TODAY. HOWEVER, WITH CURRENT
TEMPERATURES JUST BARELY BELOW ZERO, THE SNOW THAT FALLS TODAY WILL
LIKELY BE TOO HEAVY AND WET TO REACH WARNING CRITERIA.
THERE IS ALSO A RISK OF FREEZING RAIN TO THE SOUTH OF THE HEAVY SNOW
AREA THIS MORNING. SURFACE TEMPERATURES IN THE NORTHERN SAHTU REGION
WILL NEED TO BE CLOSELY MONITORED AND SHORT-FUSE FREEZING RAIN
WARNINGS WILL BE ISSUED IF NECESSARY.
NUNAVUT...THE LOW ALONG THE LABRADOR COAST CONTINUES TO FILL WHILE
TRACKING NORTHWARD TOWARDS BAFFIN ISLAND. A GENERAL PRECIPITATION
SHIELD OVER SOUTHERN BAFFIN ISLAND REMAINS, BUT A MILD AIRMASS WILL
CONTINUE TO LIMIT SNOWFALL AMOUNTS AS THIS SYSTEM CONTINUES TO DECAY.
HIGH PRESSURE BUILDS THROUGH THE KIVALLIQ AND THE MELVILLE PENINSULA
TO NORTHERN BAFFIN ISLAND, KEEPING WEATHER BENIGN AT ALL SITES UNDER
THE INFLUENCE. THE NWT LOW WILL CONTINUE TO DEVELOP AND MOVE EAST ON
FRIDAY NIGHT INTO SATURDAY. NORTH OF ITS TRACK, HEAVY SNOW WILL
AFFECT KUGLUKTUK AND CAMBRIDGE BAY TONIGHT AND SATURDAY. KUGLUKTUK IS
EXPECTED TO SEE WARMER TEMPERATURES AND THUS A LOWER SNOW-LIQUID
RATIO THROUGH THE NIGHT. WHILE TEMPERATURES ARE FORECAST TO DROP IN
THE WAKE OF THE LOW, SNOW WILL ALREADY BE TAPERING OFF BY THE TIME
THIS HAPPENS AND SO SNOWFALL AMOUNTS SHOULD REMAIN BELOW WARNING
CRITERIA. ON THE OTHER HAND, CAMBRIDGE BAY WILL REMAIN COLDER WITH
PROFILES MORE FAVOURABLE FOR RAPIDLY ACCUMULATING SNOW OVERNIGHT AND
INTO SATURDAY. STRONG NORTHWEST WINDS IN THE WAKE OF THE LOW ARE
LIKELY TO CAUSE POOR VISIBILITY IN BLOWING SNOW OVERNIGHT AND
SATURDAY FOR THESE TWO COMMUNITIES.
AS THE LOW PROGRESSES EAST, SNOW WILL REACH GJOA HAVEN BY SATURDAY
MORNING. WHILE TEMPERATURES ARE ON THE WARM SIDE FOR BLOWING SNOW,
5-10 CM OF FALLING SNOW COMBINED WITH SOUTHEASTERLY WINDS OF 50G70
KM/H OFF THE ICE IS EXPECTED TO CAUSE BLIZZARD CONDITIONS ON
SATURDAY. SNOW WILL CONTINUE INTO SUNDAY BUT WINDS ARE FORECAST TO
EASE SOMEWHAT, ALLOWING VISIBILITY TO IMPROVE.
PRECIPITATION ASSOCIATED WITH THIS LOW WILL ALSO BEGIN TO AFFECT THE
SOUTHERN KIVALLIQ ON SATURDAY MORNING. THIS SYSTEM WILL BE FUNNELING
A RELATIVELY WARMER AIRMASS NORTHWARDS, KEEPING A MILD ATMOSPHERE IN
THE SOUTHERLY WINDS. BAKER LAKE AND THE KIVALLIQ COASTAL SITES WILL
LIKELY SEE ACCUMULATING SNOW, BUT BEING RELATIVELY TEMPERATE,
SNOWFALL WARNINGS ARE NOT ANTICIPATED SUSTAINED WINDS ON THE ORDER OF
40 TO 50 KM/H ARE EXPECTED, BUT THE CONDITIONS REGARDING TEMPERATURE
PROFILES OR WIND DIRECTION ARE NOT FAVOURABLE FOR DECREASED
VISIBILITY AT ANY OF THE TOWNSITES AFFECTED.
THE EFFECTS OF THIS LOW WILL ALSO BE FELT IN THE HIGH ARCTIC.
RESOLUTE WILL SEE VERY STRONG WINDS, POSSIBLY GUSTING UP TO 90 KM/H,
ALONG WITH A FEW CENTIMETRES OF FALLING SNOW. WITH COLDER
TEMPERATURES WELL NORTH OF THE LOW AND STRONG WINDS BLOWING OFF THE
ICE, THE COMMUNITY COULD SEE OVER 24 HOURS OF NEAR-ZERO VISIBILITY
TONIGHT AND SATURDAY. CONDITIONS SHOULD IMPROVE SOMEWHAT ON SUNDAY AS
SNOW TAPERS OFF AND WINDS EASE. STRONG EASTERLIES ARE ALSO SET TO
AFFECT GRISE FIORD TONIGHT THROUGH SATURDAY MORNING. WITH WINDS
AROUND 35KT THROUGH A LOW-LEVEL INVERSION, DOWNSLOPE WIND GUSTS COULD
EXCEED 80 KM/H OVERNIGHT. A WIND WARNING MAY BE REQUIRED.
END/CARLSEN/STAUNTON
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