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FOCN45 CWWG 011900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT THURSDAY
OCTOBER 1 2026.
ALERTS IN EFFECT...STORM SURGE WARNING FOR HERSHEL ISLAND.
SYNOPTIC OVERVIEW...ALOFT, A WEAK RIDGE IS OVER WESTERN CANADA WITH
THE RIDGE AXIS OVER BC AND UP INTO NWT. THERE IS A COMPLEX OF UPPER
LOWS OVER THE EASTERN ARCTIC; WITH A NOTABLE LOW OVER THE KIVALLIQ
COAST AND ANOTHER OVER NUNAVIK. BROAD TROUGHING FROM THAT COMPLEX
EXTENDS SOUTH OVER HUDSON BAY AND ONTARIO WHERE ITS MEETS A COMPACT
VORTEX OVER NORTHWEST ONTARIO.
AT THE SURFACE, A LOW OVER ALASKA WITH TROUGHING OVER YUKON AND
MACKENZIE MOUNTAINS. A HIGH PRESSURE CENTRE SITS OVER SOUTHERN
ALBERTA. A STRONG LOW PRESSURE CENTRE IS OVER THE NUNAVIK/HUDSON
STRAIT COAST WITH TROUGHING SOUTH OVER QUEBEC.
DISCUSSION...
WESTERN PRAIRIES...SURFACE RIDGING WILL DOMINATE ALBERTA TODAY AND
CLEAR RAIN SHOWERS AND FLURRIES FROM NORTHERN SASKATCHEWAN BY
TONIGHT. A SHORTWAVE AND MODEST INSTABILITY ALONG WITH COOL
TEMPERATURES MAY ALLOW FOR A LIGHTNING STRIKE OR TWO IN ISOLATED
SHOWERS OVER FAR NORTHERN ALBERTA THIS AFTERNOON.
AN APPROACHING SHORTWAVE WILL LIKELY GENERATE MIXED PRECIPITATION
OVER THE MOUNTAIN PARKS AND FOOTHILLS, AND LIGHT RAIN SHOWERS OVER
PARTS OF SOUTHERN ALBERTA OVERNIGHT INTO FRIDAY MORNING.
EASTERN PRAIRIES...SHOWERS WILL CONTINUE TODAY AND TONIGHT OVER
CENTRAL AND NORTHERN MANITOBA AS A TRAILING COLD FRONT SWEEPS SOUTH
THROUGH THE PRAIRIES, USHERING IN COOLER AIR INTO THE REGION. SURFACE
HIGH PRESSURE BUILDS OVER THE AREA TONIGHT BUT NORTHWEST FLOW ALOFT
AND JET DYNAMICS WILL SUPPORT SPOTTY SHOWERS FRIDAY.
NWT...HIGH PRESURE WILL DEPART TODAY AND TROUGHING WILL DEVELOP
ACROSS THE TERRITORY TONIGHT. A WEAK SHORTWAVE WILL MOVE THROUGH THE
GSL REGIONS AND MAY (BIG ASTERISK HERE) ALLOW FOR A LIGHTNING STRIKE
OR TWO NEAR THE HAY RIVER TO FORT SMITH REGIONS LATE THIS AFTERNOON
INTO THIS EVENING. REGION THIS AFTERNOON.
OTHERWISE, GENERALLY SCATTERED PRECIPITATION WILL BE DEVELOPING OVER
THE MACKENZIE RIVER AND GREAT SLAVE LAKE REGIONS TONIGHT. IN THE
DELTA, MODEL CONSENSUS SUGGESTS MODEST ACCUMLUATIONS OF SNOW FOR
TONIGHT AND FRIDAY, NO MORE THAN 2 TO 4 CM PER 12 HOUR PERIOD.
SLRS HAVE BEEN DROPPED BELOW 10:1 FOR THE FIRST PART PERIOD WHEN SNOW
DEVELOPS.
A WESTERLY FLOW DEVELOPING ON THE OTHER SIDE OF THIS TROUGH WILL
ELEVATE WATER LEVELS AT HERSCHEL ISLAND BEGINNING OVERNIGHT AND
ENDING BY NOON FRIDAY.
NUNAVUT...THE LOW OVER NUNAVIK WILL CONTINUE PRECIPITATION FOR THE
COMMUNITIES IN THE KIVALLIQ AND SOUTHERN BAFFIN ISLAND FOR THE NEXT
24 TO 48 HOURS. TOTAL PRECIPITATION AMOUNTS WILL BE 10 TO 20 MM OF
SHOWERS MIXED WITH FLURRIES, AT TIMES. GUSTY EASTERLY WINDS OF 60 TO
70 KM/H ARE EXPECTED FOR SOUTHERN BAFFIN ISLAND WHICH WILL IMPROVE
THIS EVENING AS THE LOW FLATTENS OUT. AT THE SAME TIME, THE GRADIENT
WILL TIGHTEN OVER THE COASTAL COMMUNITIES OF THE KIVALLIQ, CREATING
GUSTS OF 70 TO 80 KM/H WHICH WILL LAST UNTIL FRIDAY.
STRONG NORTHERLY WINDS ARE POSSIBLE AT GRISE FIORD THIS AFTERNOON AND
TONIGHT. NORTHERLY FLOWS THIS STRONG HAVE CLIMATOLOGICALLY GENERATED
GUSTS OF 90 KM/H OR MORE IN THE HAMLET BEFORE BUT WE DO HAVE SOME
QUESTIONS ABOUT THE STRENGTH OF THE INVERSION. ANALOGUES SUGGEST
USUALLY ONE WOULD WANT A STRONGER INVERSION, MORE OFTEN PRESENT IN
WINTER, TO ENHANCE WINDS ENOUGH AT THE TOWNSITE. WITH LOW CONFIDENCE
GUSTS OF 80 KM/H HAVE BEEN INDICATED FOR THIS PERIOD, WITH 60 KM/H
TONIGHT INTO TOMORROW.
NORTHERLY WINDS WILL ALSO BE FAIRLY STRONG IN RESOLUTE, IN THE 40G60
KM/H RANGE. WITH 4 CM OF LOOSE DRY SNOW ON THE GROUND A THOUGHT WAS
GIVEN TO ADDING BLOWING SNOW AT TIMES TO THE FORECAST, BUT SIMILAR
SUSTAINED WINDS ONLY CAUSED DRIFTING SNOW AT THE SITE YESTERDAY AND A
FORECAST HIGH OF MINUS 1 MAY ALLOW FOR THE SNOWPACK TO BECOME A BIT
WETTER BEFORE WINDS KICK IN.
END/BILOUS/BATE/PIMISKERN
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