PASPC Thunderstorm Outlook Day 1

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FOCN45 CWWG 202000

SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CST MONDAY NOVEMBER 20 2017.

ALERTS IN EFFECT...BLIZZARD WARNING FOR CAPE DORSET, HALL BEACH, IGLOOLIK, ALL OF NORTHERN AND SOUTHERN KIVALLIQ, SAVE FOR CHESTERFIELD INLET, AND CHURCHILL. BLIZZARD WARNING ALSO TO BE ISSUED FOR RESOLUTE THIS AFTERNOON. WIND WARNINGS FOR IQALUIT, KIMMIRUT, PANGNIRTUNG, AND GRISE FIORD. SNOWFALL WARNINGS FOR KUGAARUK, NORTHERN SASKATCHEWAN AND CENTRAL MANITOBA.

SYNOPTIC OVERVIEW...H500 ANALYSIS SHOWING TROUGHS OVER WESTERN ARCTIC, HUDSON BAY AND A SHORTWAVE TROUGH MOVING THROUGH NORTHERN SASKATCHEWAN, WITH A HIGHLY-AMPLIFIED UPPER RIDGE OVER THE DAVIS STRAIT. AT THE SURFACE, 18Z ANALYSIS SHOWING 990 MB LOW JUST NORTH OF WINNIPEG WITH WARM FRONT ESE AND COLD FRONT WEST. 979 MB LOW OVER NORTHERN QUEBEC WITH TROUGH STRETCHING WEST OVER HUDSON BAY.

DISCUSSION...

EASTERN ARCTIC...STRONG PRESSURE GRADIENT NOW IN PLACE OVER MUCH OF EASTERN ARCTIC WILL CONTINUE TO STRENGTHEN TODAY AND PUSH NORTHWARD AS LOW PRESSURE SYSTEM OVER LABRADOR MOVES WESTNORTHWESTWARD. THIS LOW IS ALSO BRINGING LOTS OF MOISTURE FROM THE SOUTH. NET RESULT OF ALL THIS WILL BE BLIZZARD CONDITIONS WITH STRONG EASTERLY WINDS WHERE SUFFICIENT SNOW FALLS, WITH WATCHES OR WARNINGS TO THAT EFFECT IN PLACE FOR MUCH OF THE AREA. AS THE LOW CONTINUES TO TRACK WEST-NORTHWESTWARD ACROSS HUDSON BAY, A STRONG NORTHWEST GRADIENT ESTABLISHES ITSELF OVER THE COMMUNITIES OF THE SOUTHERN KIVALLIQ. FALLING SNOW COMBINED WITH NORTHWESTERLY WINDS OF 60 GUSTING TO 80 KM/H WILL BRING BLIZZARD CONDITIONS TO THESE AREAS TUESDAY MORNING, THEREFORE WINTER STORM WATCHES WILL BE UPGRADED WITH THE AFTERNOON FORECAST ISSUE. HOWEVER, WARNINGS WILL NOT BE ISSUED FOR CHESTERFIELD INLET AS THEY WILL NOT EXPERIENCE THE SAME WINDS AS THE REST OF SOUTHERN KIVALLIQ AS THEY WILL BE IN THE TROUGH ASSOCIATED WITH THE LOW, THEREFORE WINDS WILL BE LIGHTER. ALTHOUGH CHESTERFIELD INLET IS NOT EXPECTED TO SEE BLIZZARD CONDITIONS TOMORROW, THEIR WINDS WILL STILL BE NORTHWEST 50 GUSTING TO 70 KM/H AND WITH SOME FALLING SNOW, THEY WILL SEE SOME REDUCED VISIBILITIES IN BLOWING SNOW. IN ADDITION, KUGAARUK IN THE KITIKMEOT REGION WILL SEE HEAVY SNOW STARTING TONIGHT WITH TOTAL ACCUMULATIONS OF NEAR 20 CM EXPECTED BY TUESDAY NIGHT. WIND GUSTS TO 60 KM/H WILL COMBINE WITH THE FALLING SNOW TO REDUCE VISIBILITIES AT TIMES TO NEAR ZERO. STRONG WINDS AND HIGH SNOWFALL ACCUMULATIONS COULD ALSO LEAD TO LARGE SNOWDRIFTS AROUND STRUCTURES. COMMUNITIES THAT DON'T SEE MUCH SNOW WITH THIS SYSTEM WILL NEVERTHELESS FEEL THE IMPACT WITH DAMAGING EASTERLY WINDS GUSTING AS HIGH AS 110 KM/H EXPECTED IN KIMMIRUT, IQALUIT AND PANGNIRTUNG. GRISE FIORD WILL ALSO SEE THE STRONG EASTERLY WINDS, HOWEVER, THEY WILL NOT SEE ANY FRESH SNOW. THE MAIN ISSUE FOR GRISE FIORD IS THE WIND DIRECTION. THE DIRECTION IS SLIGHTLY TOO SOUTH OF EAST, WHICH MAY BE ENOUGH TO NOT REACH WARNING LEVEL WINDS TODAY BUT LOOKING INTO TUESDAY, THE WINDS WILL SHIFT SLIGHTLY NORTH OF EAST WHICH WILL BE MORE FAVOURABLE FOR WARNING LEVEL WINDS WITH GUSTS TO 90 KM/H OR POSSIBLY MORE.

PRAIRIES...FAST MOVING CLIPPER CROSSES THE PRARIES TODAY. ABOUT 10 CM SNOW FELL THROUGH PARTS OF CENTRAL AND NORTHERN SASKATCHEWAN LAST NIGHT, AND THIS WILL CONTINUE AS THE SYSTEM MOVES THROUGH MANITOBA, WITH THE HIGHEST AMOUNTS EXPECTED FROM THE PAS/FLIN FLON THROUGH GRAND RAPIDS THEN ON INTO BERENS RIVER AND POPLAR RIVER. BEHIND THE COLD FRONT THERE ARE SOME CONVECTIVELY ENHANCED LOCALIZED +SHSN WITH REPORTS OF NEAR 10 CM OF SNOW IN A FEW LOCALITIES IN EAST CENTRAL SASKATCHEWAN, THEREFORE LOCAL HIGHER AMOUNTS OF SNOW HAVE BEEN ADDED TO THE PUBLIC FORECASTS. STRONG NORTHERLY WINDS BEHIND THE COLD FRONT ARE GIVING REDUCED VISIBILITIES IN BLOWING SNOW. WINDS ARE USHERING IN COLDER AIR BEHIND THE COLD FRONT THAT ARE CAUSING TEMPERATURES TO FALL FOR AREAS PREVIOUSLY IN THE WARM SECTOR, WHERE TEMPERATURES REMAINED A FEW DEGREES ABOVE ZERO LAST NIGHT. AS A RESULT, ALBERTA IS EXPERIENCING A FALLING TEMPERATURE TREND TODAY AS MANY PLACES THROUGHOUT THE PROVINCE ARE APPROACHING -20C THIS AFTERNOON. STRONG GUSTY WINDS WILL BRING WINDS CHILL VALUES CLOSE TO -30.

LOW THAT IS IMPACTING AREAS OVER BAFFIN ISLAND AND KIVALLIQ WILL ALSO BRING A STRONG NORTHWEST GRADIENT OVER CHURCHILL. STRONG NORTHWESTERLY WINDS OF 60 GUSTING TO 90 KM/H COMBINED WITH FALLING SNOW WILL BRING BLIZZARD CONDITIONS TO CHURCHILL TOMORROW MORNING.

LOOKING AHEAD AT TUESDAY NIGHT INTO WEDNESDAY MORNING, WARM AIR MOVING IN ALOFT IN A WESTERLY FLOW, COMBINED WITH COLD SURFACE TEMPERATURES WILL TEAM UP TO SET THE STAGE FOR SOME POSSIBLE FREEZING RAIN SOUTHEST OF RED DEER TO THE ALBERTA/SASKATCHEWAN BORDER. ADDITIONALLY, WARNING LEVEL WINDS WITH GUSTS OF 100-110 KM/H ARE POSSIBLE AGAIN FOR EXTREME SOUTHWESTERN ALBERTA BEGINNING TUESDAY NIGHT. MORE SNOW IS ALSO POSSIBLE FOR THE GRANDE CACHE AND JASPER REGIONS WITH 5-10 CM OF SNOW LIKELY FOR THESE AREAS.

END/MOODIE/GREENHOUGH