996
FOCN45 CWWG 261900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT FRIDAY JULY
26 2024.
ALERTS IN EFFECT...HEAT WARNINGS FOR PORTIONS OF SOUTHERN MANITOBA
AND FOR ISLAND LAKE AS WELL AS PARTS OF NORTHERN NWT. AIR QUALITY
ADVISORY OVER NORTHWESTERN MANITOBA, NORTHERN SASK, SOUTHERN
ALBERTA, AND SOUTHERN NWT. RAIN AND WIND WARNINGS FOR PARTS OF
CENTRAL AND NORTHERN ALBERTA.
SYNOPTIC OVERVIEW...ALOFT, THE OMEGA BLOCKING PATTERN HAS BEGUN TO
BREAK DOWN. RIDGING OVER THE EASTERN PACIFIC POKES INTO YUKON
TERRITORY AND WESTERN NWT. DEEP LOW CENTRE SPINS OVER THE NORTHERN
AB/SK BORDER. RIDGING FROM THE US MIDWEST CONTINUES INTO SOUTHERN
HUDSON BAY VIA NORTHWESTERN ONTARIO. BROAD CYCLONIC FLOW OVER THE
EASTERN ARCTIC IS ANCHORED BY A LOW CENTRE OVER BAFFIN BAY.
AT THE SURFACE, HIGH PRESSURE IS OVER THE EASTERN PACIFIC WITH A
RIDGE AXIS EXTENDING INTO BC, YUKON, AND CENTRAL ARCTIC. AN OCCLUDED
LOW IS OVER NORTHERN SASKATCHEWAN, NEAR LAKE ATHABASCA. ASSOCIATED
COLD FRONT EXTENDS SOUTHWESTWARDS THROUGH WESTERN MANITOBA AND INTO
THE DAKOTAS. THE WARM FRONT DRAPES EASTWARD THROUGH NORTHERN
MANITOBA AND THEN DIPS SOUTHWARD THROUGH NORTHWESTERN ONTARIO. A
RIDGE OF HIGH PRESSURE EXTENDS THROUGH ONTARIO AND INTO HUDSON BAY.
A TROUGH OF LOW PRESSURE IS OVER BAFFIN BAY AND DAVIS STRAIT WITH A
986 MB LOW NEAR QIKIQTARJUAQ.
DISCUSSION...
PRAIRIES...HEAT WARNINGS WILL CONTINUE FOR A SLIVER OF SOUTHEASTERN
MANITOBA AHEAD OF THE ADVANCING COLD FRONT. WARNINGS LOOK TO HANG ON
FOR ONE MORE DAY, BEFORE COMING TO AN END FOR SUNDAY.
WESTERLY WINDS DEVELOPING BEHIND THE COLD FRONT WILL PERMIT WILD
FIRE SMOKE FROM THE BC INTERIOR TO CROSS SOUTHERN ALBERTA AND ENTER
A MAJORITY OF SOUTHERN SASKATCHEWAN. UNCERTAINTY EXISTS REGARDING THE
CONCENTRATION OF SMOKE TO SURFACE SO UPSTREAM OBS WILL BE A
DETERMINING FACTOR. SAQS AND/OR AN EXPANSION OF THE AQA MAY BE
WARRANTED.
WESTERLY GUSTS UP TO 80 KM/H ARE EXPECTED ON THE SOUTHERN FLANK OF
THE NORTHERN SASKATCHEWAN LOW, THROUGH PORTIONS OF CENTRAL ALBERTA
AND THE NORTHERN GRAINBELT TOWARDS SASKATOON, TODAY. COULD SEE THE
ODD GUST APPROACH 90 KM/H, ESPECIALLY DOWNSTREAM OF LESSER SLAVE
LAKE AND NEAR THE AB/SK BORDER DURING THE LATE MORNING AND EARLY
AFTERNOON. WINDS PROGGED TO DIMINISH SOMEWHAT LATER IN THE AFTERNOON
AS THE LOW BEGINS TO FILL AND MOVE EASTWARDS.
HEAVY RAIN IS ALSO OCCURRING WITH THE THIS SYSTEM WITH THE GREATEST
AMOUNTS REPORTED OVERNIGHT IN THE 30-60 MM RANGE. THE RAIN WILL PUSH
EASTWARD TODAY WITH THUNDERSTORMS ENHANCING PRECIP AMOUNTS NORTH OF
THE LOW.
FOR CONVECTION, TODAY, NON-SEVERE STORMS WILL PERSIST ABOUT THE LOW
CENTRE AND POINTS EAST OVER THE NORTHERN PRAIRIES. THE SEVERE
THUNDERSTORM ACTIVITY WILL BE CONFINED TO THE COLD FRONT CUTTING
THROUGH EASTERN MANITOBA. OVER WESTERN MANITOBA AND THE INTERLAKE
REGION, RESIDUAL CONVECTION CONTINUES FROM THE OVERNIGHT, BUT
CLEARING IS EVIDENT OVER SOUTHEASTERN MANITOBA, ALLOWING FOR MAXIMUM
HEATING. THE COLD FRONT WILL BE TRACKING THROUGH THIS REGION THIS
AFTERNOON. AMPLE LIFT ALONG THE FRONT WILL ALLOW RISING AIR TO
INTERACT WITH AN ENVIRONMENT LADEN WITH BOTH GOOD THERMODYNAMICAL
AND DYNAMIC SUPPORT. AMPLE MOSITURE THROUGH THE COLUMN WILL HELP
BREED MLCAPES OF 1000+ J/KG. STRONG DIRECTIONAL/SPEED SHEAR VEERING
PROFILES TO LEAD TO BULK SHEARS OF 30 TO 40 KTS. MLCAPE INCREASES TO
NEAR 2000 ALONG A NARROW CORRIDOR VC BORDER WITH MINNESOTA BY 21Z
FRIDAY. A SUPERCELL OR TWO IS POSSIBLE WITH INITATION IN THIS
REGION, ESPECIALLY IF AIDED BY A MIGRATING LAKE BREEZE BOUNDARY.
MAIN THREATS IN THIS EXTREME SOUTHEASTERN SECTION OF THE PROVINCE
INCLUDES LARGE HAIL, DAMAGING WIND GUSTS AND POSSIBLY A TORNADO. THE
COLD FRONT WILL TRACK INTO NORTHWESTERN ONTARIO EARLY THIS EVENING,
PUSHING THE SEVERE THUNDERSTORM THREAT OUT OF THE AOR. HOWEVER,
LINGERING STORMS BEHIND THE COLD FRONT MAY PERSIST OVER SOUTHEASTERN
MANITOBA INTO THE LATE EVENING/OVERNIGHT. FUTHER NORTH, THROUGH
EAST-CENTRAL REGIONS, MLCAPE VALUES DROP OFF AND THUS, SO TOO DOES
THE TORNADO RISK. THAT BEING SAID, AMPLE CAPE/SHEAR EXISTS FOR LARGE
HAIL COUPLED WITH GUSTS TO 90 KM/H.
WESTERN ARCTIC...THIS IS THE LAST EXPECTED DAY OF THE CURRENT HEAT
EVENT FOR AREAS FROM NORMAN WELLS TO INUVIK. SMOKE CONTINUES TO
IMPACT MANY SITES IN THE NWT FROM NEARBY FIRES. TOMORROW, THERE IS A
CHANCE OF SEVERE PULSE THUNDERSTORMS THROUGH THE CENTRAL
MACKENZIE VALLEY ASSOCIATED WITH AN AREA OF LOW PRESSURE.
EASTERN ARCTIC...THE NORTHERN FLANK OF THE PRECIP SHIELD ASSOCIATED
WITH THE NORTHERN PRAIRIE LOW WILL CLIP ARVIAT STARTING FRIDAY NIGHT
WITH PERSISTENT RAINFALL THAT WILL CONTINUE INTO SATURDAY EVENING.
TOTAL AMOUNTS OF 10 TO 20 MM ARE EXPECTED.
RAIN WILL PULL AWAY FROM EASTERN BAFFIN TODAY AS THE LOW
RESPONSIBLE ENTERS DAVIS STRAIT. ANOTHER SYSTEM WILL RIDE THE
BAROCLINIC ZONE, DOWN FROM THE HIGH ARCTIC, REACHING NORTHERN
BAFFIN AND THE MELVILLE PENINSULA COME SATURDAY. THE MAJORITY OF THE
HIGHEST QPF WILL FALL OVER THE UNINHABITED INTERIOR BAFFIN
HIGHLANDS, BUT LIGHT PRECIP WILL FALL THROUGH THE DAY ON SUNDAY AS
THE LOW MIGRATES TOWARDS THE SOUTHEAST. NORTHWESTERLY GUSTS
APPROACHING 70 KM/H ON THE BACKSIDE OF THIS SYSTEM ARE EXPECTED FOR
SANIRAJAK AND IGLOOLIK LATE SATURDAY NIGHT THROUGH SUNDAY MORNING.
END/SPC-WPG/PIMISKERN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page