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FOCN45 CWWG 152000
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CST WEDNESDAY
JANUARY 15 2025.
ALERTS IN EFFECT...SNOWFALL WARNING FOR PARTS OF NORTHERN ALBERTA AND
NORTHERN SASKATCHEWAN AS WELL AS FORT LIARD. SNOWFALL WARNINGS
FORTHCOMING FOR CENTRAL MANITOBA.
SYNOPTIC OVERVIEW...ALOFT, A STRONG H25 JET RIDES THE RIDGE OVER THE
PACIFIC NORTHWEST, ARCING FROM THE PACIFIC, THROUGH THE CENTRAL BC
COAST BEFORE DIVING SOUTHEASTWARDS ACROSS THE SOUTHERN PRAIRIES.
SHORTWAVE OVER NORTHERN MANITOBA HEADS SOUTHEASTWARDS WITH THE
STEERING FLOW. OVER THE EASTERN ARCTIC, A BROAD CYCLONIC FLOW EXISTS,
ANCHORED BY A CENTRE OVER BAFFIN BAY.
AT THE SURFACE, A NORTH-SOUTH RIDGE STRETCHES FROM THE US SOUTHWEST,
ALL THE WAY UP TO ALASKA. LOW CENTRE VC YORK WITH COLD FRONT ALONG
THE 60TH PARALLEL AND WARM FRONT SOUTH OF THE LOW, BISECTING MANITOBA
EAST-WEST. WARM, PACIFIC FLOW OVER THE WESTERN PRAIRIES. LOW CENTRE
OFF THE SOUTHERN TIP OF BANKS ISLAND. RIDGE FROM THE HIGH ARCTIC INTO
FOXE BASIN. TROUGHING OVER EASTERN DAVIS STRAIT.
DISCUSSION...
AB/NRN SK...ONE MORE DAY OF ABOVE SEASONAL, ABOVE FREEZING
TEMPERATURES IS ON TAP FOR ALBERTA BEFORE THE TABLES TURN ON
THURSDAY. A LOW IS FORECAST TO DEVELOP OVER NORTHWESTERN ALBERTA
TONIGHT AND TRACK SOUTHEAST THROUGH THE DAY ON THURSDAY. HEAVY SNOW
WILL BEGIN IN NORTHERN ALBERTA THIS EVENING, SPREADING INTO NORTHERN
SASKATCHEWAN BY THURSDAY MORNING. THE HEAVIEST SNOW IS EXPECTED
THROUGH THE DAY ON THURSDAY BEFORE IT TAPERS OFF ON THURSDAY NIGHT.
A BROAD SWATH OF 15 TO 25 CM IS EXPECTED FROM HIGH LEVEL THROUGH
CUMBERLAND HOUSE BY FRIDAY MORNING.
ON THE SOUTHERN FRINGE OF THE SNOWFALL WARNING, THERE IS A RISK OF
FREEZING RAIN STRETCHING FROM ABOUT MANNING THROUGH COLD LAKE.
PROG SOUNDINGS INDICATE RELATIVELY SHALLOW AFLS WITH SURFACE
TEMPERATURES NEAR ZERO, SO THE FREEZING RAIN RISK IS LIKELY FAIRLY
MINIMAL. HOWEVER IF THE THREAT DOES INCREASE WINTER STORM WARNINGS
MAY NEED TO BE ISSUED IN THIS AREA. STRONG WINDS WILL ALSO BE A
CONCERN WITH THIS SYSTEM ACROSS MUCH OF THE PROVINCE.
FIRSTLY, AS THE COLD FRONT ASSOCIATED WITH THIS SYSTEM SWEEPS SOUTH
THROUGH ALBERTA THURSDAY, IT MAY TRIGGER SOME LOCALIZED BRIEF GUSTS
TO 90 KM/H FROM PEACE COUNTRY RIGHT DOWN THROUGH SOUTHEASTERN ALBERTA
AS STRONG WINDS MIX DOWN FROM ALOFT. AS THE COLD FRONT MARCHES SOUTH,
IT WILL GENERATE A FAIR AMOUNT OF INSTABILITY FOR THE MIDDLE OF
WINTER (UPWARDS OF 200 J/KG OF MUCAPE). THUS THERE IS A SLIGHT
POSSIBILITY OF A FEW LIGHTNING STRIKES ALONG THE FRONT AS LOW TOPPED
CONVECTION DEVELOPS ALONG IT. WITH SHARP LAPSE RATES EXCEEDING 9 DEG
C PER KM, PARTICULARLY ABOVE 850 HPA...AND SOME BOUNDARY LAYER
MOISTURE DUE TO RECENT MELTING SNOW...THE POSSIBILITY EXISTS FOR
FRONTAL SNOW SQUALLS TO DEVELOP AND TRACK SOUTHEAST ALONG THE HWY 43
CORRIDOR BETWEEN GRANDE PRAIRIE AND EDMONTON DURING THE MORNING. ANY
SNOW THAT FALLS SHOULD BE FAIRLY WET AND POSSIBLY MIXED WITH RAIN,
SO THE CONCERN IS NOT NECESSARILY ACCUMULATIONS. THE MAIN CONCERN IS
POTENTIALLY SIGNIFICANT WINDS AND BRIEF BURSTS OF SNOW COMBINING TO
REDUCE VISIBILITY TO NEAR ZERO ON HEAVILY TRAVELED ROUTES.
THE MORE WIDESPREAD THREAT FOR STRONG WINDS WILL COME AS A LOW-LEVEL
JET BEGINS TO DEVELOP AND INTENSIFY BEHIND THE COLD FRONT. OPEN AREAS
OF NORTHWESTERN ALBERTA INCLUDING GRANDE PRAIRIE, PEACE RIVER AND
SLAVE LAKE ARE AT RISK OF SEEING WIND GUSTS EXCEEDING 90 KM/H
BEGINNING THURSDAY MORNING IN THE WAKE OF THE FRONT. SECONDLY, PARTS
OF EAST-CENTRAL ALBERTA ARE UNDER THE SAME WIND THREAT LATER IN THE
DAY AS THE LOW-LEVEL JET CONTINUES TO INTENSIFY. AGAIN, THE MOST
LIKELY AREA TO SEE WIND WARNINGS IS THE OPEN PRAIRIE TO THE EAST/
SOUTHEAST OF EDMONTON. FINALLY, ONGOING GAP WINDS THROUGH CROWSNEST
PASS WILL RAMP UP BY THURSDAY AFTERNOON, WITH WIND GUSTS IN EXTREME
SOUTHWESTERN ALBERTA LIKELY REACHING 100 KM/H. STRONG WINDS MAY
BECOME MORE WIDESPREAD ALONG THE SOUTHERN FOOTHILLS IN THE AFTERNOON
AS THE COLD FRONT SWEEPING THROUGH IS EXPECTED TO LIFT THE INVERSION
IN THE AREA THAT IS FORCING THE WINDS OUT CROWSNEST PASS. THIS MAY
SET UP A BRIEF PERIOD OF DOWNSLOPE WINDS BEFORE THE INVERSION LIFTS
TOO HIGH TO BE OF ANY CONSEQUENCE.
FINALLY MB/SK...LIGHT SNOW WILL CONTINUE OVER MOST OF THE PROVINCE
TODAY AS THE YORK LOW HEADS TOWARDS SOUTHERN HUDSON BAY TONIGHT.
FOLLOWING THAT, A LOW PRESSURE SYSTEM WILL DEVELOP OVER NORTH-CENTRAL
ALBERTA ON THURSDAY AND THEN TRACK SOUTHEAST OVER THE FOLLOWING 24
HOURS. THIS WILL SPREAD A SWATH OF 10 TO 20 CM OF SNOW ACROSS THE
NORTHERN PRAIRIES THAT REACHES EAST-CENTRAL SASKATCHEWAN AND
WEST-CENTRAL MANITOBA BY THURSDAY AFTERNOON. THIS BAND OF SNOW WILL
CONTINUE EAST ACROSS CENTRAL MANITOBA ON THURSDAY INTO FRIDAY.
SNOWFALL WARNINGS WILL BE FORTHCOMING WITH THE AFTERNOON FORECAST
ISSUE.
MUCH OF THE SOUTHERN PRAIRIES WILL EXPERIENCE VERY MILD TEMPERATURES
THROUGH THE LATTER HALF OF THE WEEK, BUT WITH THE PASSAGE OF THE
ALBERTA LOW, A SIGNIFICANT CHANGE IN THE WEATHER PATTERN WILL DEVELOP
AND ARCTIC AIR WILL FLOOD SOUTHWARDS THROUGH THE CANADIAN PRAIRIES
AND THEN MUCH OF NORTH AMERICA. IN ADDITION, BLOWING SNOW WILL BE A
CONCERN ACROSS MUCH OF THE SOUTHERN PRAIRIES WITH THE PASSAGE OF THE
COLD FRONT THURSDAY NIGHT AND FRIDAY. FOLLOWING THAT, BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS WILL REDEVELOP OVER THE
PRAIRIES ON THE WEEKEND AND LAST INTO NEXT WEEK.
NT...THE SOUTHWEST CORNER OF THE NT WILL BE CLIPPED BY THE SYSTEM
DEVELOPING IN THE PRAIRIES. UPSLOPE NORTHEASTERLY FLOW WILL LIKELY
HELP TO ENHANCE SNOWFALL AMOUNTS IN THE FORT LIARD AREA, WITH 10 TO
15 CM EXPECTED TONIGHT THROUGH THURSDAY MORNING. SNOWFALL AMOUNTS
WILL TAPER OFF QUICKLY MOVING NORTHEAST TOWARDS THE MACKENZIE VALLEY.
NU...EXTREME COLD MAY RETURN TO NORTHERN BAFFIN ISLAND AND MELVILLE
PENINSULA COMMUNITIES, AS WELL AS MUCH OF THE KITIKMEOT AND RESOLUTE
WEDNESDAY NIGHT INTO THURSDAY. AS HIGH PRESSURE BUILDS OVER THE NWT
THURSDAY NIGHT INTO FRIDAY, THE GRADIENT OVER THE SOUTHERN KIVALLIQ
WILL BEGIN TO TIGHTEN AND BLOWING SNOW MAY BECOME A CONCERN FOR SOME
OF THE COASTAL COMMUNITIES ON FRIDAY.
THE METEOROLOGICAL SERVICE OF CANADA IS INVESTIGATING THE
DISCONTINUATION OF THIS SIGNIFICANT WEATHER DISCUSSION. IF YOU USE
THIS BULLETIN AND HAVE ANY COMMENTS OR CONCERNS, PLEASE CONTACT US AT
FOCN45@EC. GC. CA WITH THE SUBJECT: "SIGNIFICANT WEATHER DISCUSSION
FEEDBACK" INCLUDE YOUR ORGANIZATION AND HOW YOU USE THIS PRODUCT.
END/SPC-YWG/VAN LOCHEM
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