040
FOCN45 CWWG 061900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT MONDAY APRIL
6 2026.
ALERTS IN EFFECT...SNOWFALL WARNING FOR A SWATH OF NORTHERN ALBERTA.
BLIZZARD WARNINGS FOR BAKER LAKE, ARVIAT, RANKIN INLET, AND NAUJAAT.
FOG AND FREEZING DRIZZLE ADVISORIES FOR CALGARY AND SURROUNDING
AREAS. SPECIAL WEATHER STATEMENTS FOR PORTIONS OF CENTRAL
SASKATCHEWAN AND THE ALBERTA ROCKIES.
SYNOPTIC OVERVIEW...ALOFT, DEEP UPPER TROF OVER WESTERN ALASKA AND
THE GULF OF ALASKA SOUTHWARD TOWARDS HAIDA GWAII WITH A NORTHWESTERLY
FLOW OVER WESTERN CANADA. UPPER HIGH OVER THE BEAUFORT SEA AND UPPER
LOW OVER BAFFIN ISLAND. NORTHERLY FLOW OVER THE NORTHERN ARCTIC.
AT THE SURFACE, THERE ARE A SERIES OF WEAK LOWS FROM THE GULF OF
ALASKA TO NORTHERN ALBERTA, THE MOST NOTABLE OF WHICH IS A 1009 MB
LOW OVER NORTHWESTERN BC. 1040 MB HIGH OVER CENTRAL SK. 990 MB LOW
OVER LABRADOR.
DISCUSSION...
WESTERN PRAIRIES...A DIGGING UPPER TROUGH WILL DEVELOP AN ALBERTA
CLIPPER TODAY. SNOW WILL BE SRPEADING EASTWARDS ACROSS A WARM FRONT,
REACHING PEACE RIVER IN THE NEXT FEW HOURS AND THE SASKATCHEWAN
BORDER BY THE EVENING. THE SNOWFALL FORECAST IS SOMEWHAT COMPLICATED
DUE TO POOR AGREEMENT IN GUIDANCE, BUT A REPS AVERAGE DICTATES THAT
THE HEAVIEST SNOWFALL WILL FALL NORTH OF THE TRACK OF A FRONTAL WAVE
THAT WILL BE NORTH OF THE SURFACE LOW, IN A SWATH FROM PEACE RIVER TO
COLD LAKE, AND LIKELY SOUTH OF FORT MCMURRAY AND MORE LIKELY THAN NOT
NORTH OF THE SMOKY LAKE, THOUGH THIS IS ALOT LESS CERTAIN. SNOW WILL
LINGER IN A TROWAL HANGING BACK FROM THE LOW TOMORROW AS IT DEPARTS.
SNOWFALL AMOUNTS WILL GENERALLY BE IN THE 10 TO 15 CM RANGE IN THIS
SWATH, THOUGH COULD BE HIGHER NEAR THE BC BORDER. SLRS ARE EXPECTED
TO BE NEARISH 10:1 AS THE SYSTEM ARRIVES AT NIGHT AND TEMPERATURES
WILL START BELOW ZERO.
A LOT OF UNCERTAINTY REMAINS WITH THIS FORECAST. FIRST IS THE TRACK
OF THE FRONT AND SWATH OF SNOW ITSELF, SOMETIMES PLACED SOMEWHAT
FURTHER SOUTH SUCH AS IN THE CURRENT RDPS. SECOND IS THE POTENTIAL
FOR INSTABILITY TO INCREASE SNOWFALL AMOUNTS IN CONVECTIVE BANDS BOTH
NORTH OF THE LOW AND ALONG A COLD FRONT TRAILING IT. ALL THAT SAID,
CONFIDENCE IS NOT HIGH ENOUGH TO EXPAND THE SNOWFALL WARNING UNTIL
LATER...PERHAPS AS THE SNOWFALL DEVELOPS.
THE TRAILING COLD FRONT WILL ALSO BRING SOME PROBLEMATIC WEATHER.
SOME INSTABILITY COMBINED WITH A REASONABLE ISALLOBARIC PUSH WILL
PROBABLY BRING HIGH SNOWFALL RATES TO PORTIONS OF THE ROCKY MOUNTAINS
AND PERHAPS OTHER AREAS. EXACT SNOWFALL AMOUNTS ARE HARD TO PIN DOWN
DUE TO A WARM AFTERNOON POSSIBLY HEATING THE GROUND AND REDUCING SLRS
AND DUE TO THE CONVECTIVE NATURE OF THE SNOW. NONETHELESS, GIVEN
MULTIPLE GUIDANCE SUGGESTING SNOWFALL RATES NEAR 4 CM/HR ALONG WITH
SOME INSTABILITY ALONG THE COLD FRONT, A SPECIAL WEATHER STATEMENT
REMAINS IN EFFECT FOR THE ROCKIES AND FOOTHILLS. INSTABILITY MAY BE
GREATER TOMORROW, INCREASING THE POTENTIAL FOR HEAVY FLURRIES FURTHER
SOUTH, THOUGH, AGAIN, SIGNIFICANT UNCERTAINTIES HERE.
IN THE WAKE OF THE COLD FRONT, THERE WILL BE A DECENT ISALLOBARIC
PUSH ALLOWING FOR WIND GUSTS UP TO 70 KM/H OVER PORTIONS OF CENTRAL
ALBERTA. SIMILAR STRONG WINDS ARE POSSIBLE IN PINCHER CREEK TONIGHT,
WEST OF TROUGHING IN DOWNSLOPE WINDS.
EASTERN PRAIRIES...FOR A CHANGE OF PACE FROM THIS WINTER, ANOTHER
ALBERTA CLIPPER! AS THE UPPER TROF OVER THE GULF OF ALASKA COMES
ONSHORE TODAY, IT WILL BOLSTER INTO A CLOSED LOW OVER NORTHERN BC,
WITH A 95KT H500 JET ROUNDING THE BASE. THE SURFACE LOW WILL DEVELOP
WITHIN THE LEE TROF NEAR THE AB FOOTHILLS OVERNIGHT MONDAY NIGHT INTO
TUESDAY MORNING. THE TRACK OF THE LOW WILL INITIALLY BE TO THE
SOUTHEAST INTO MONTANA, BUT THEN EASTWARD, AS THE RIDGING AHEAD OF
THE SYSTEM FLATTENS TO A MORE ZONAL FLOW OVER THE NORTHERN US PLAINS.
THERE IS A FAIR BIT OF AGREEMENT IN NUMERICAL GUIDANCE IN THE SPEED
AND TRACK OF THIS LOW. UNFORTUNATELY, ITS HAPPENING. WHAT THAT MEANS
IS A BIT MORE IN QUESTION.
AS ALWAYS WITH THESE SHOULDER SEASON SYSTEMS, THE REALIZED WEATHER IS
A CHALLENGE TO FORECAST. THERE WILL BE A CONSIDERABLE AMOUNT OF
ISENTROPIC ASCENT OVER CENTRAL SASKATCHEWAN, WITH A FAIR BIT OF
INSTABILITY. HEAVY SNOW WILL FALL IN A CORRIDOR FROM MEADOW LAKE, SK
THROUGH PRINCE ALBERT, TOWARDS SWAN RIVER, MB. PROFILES SHOW A
FAVOURABLE ATMOSPHERIC COLUMN FOR SNOW PRODUCTION ALONG THE NORTHERN
FLANK OF THE SYSTEM TRACK, GENERALLY 10 TO 15 CM OF SNOWFALL
EXPECTED. RECENT WARMTH, REDUCED SNOWPACK, AND THE EFFECT OF HIGH SUN
ANGLE DUE TO THE TIME OF YEAR, THERE WILL MELTING AND COMPACTION
AHEAD OF THE ACCUMULATION, REDUCING THE EFFECTIVE SNOW TOTALS FOR THE
EVENT. WHEN THAT TRANSITION FROM MELTING TO ACCUMULATION OCCURS WILL
DETERMINE HOW MUCH EFFECTIVE SNOWFALL THERE WILL BE. THE ACTUAL
SNOWFALL ITSELF MAY END UP NOT HITTING 15 IN 24 HOUR CRITERIA.
IN THE WARM SECTOR, THERE WILL ALSO BE A RISK OF FREEZING RAIN ALONG
THE WARM FRONT WITH PERISTANT WARM AIR ADVECTION TO SUSTAIN THE
PROCESS. SURFACE TEMPS WILL GENERALLY BE ABOVE ZERO IN THE WARM
SECTOR HOWEVER AND THE RESULTANT BAND OF RISK WILL BE QUITE NARROW.
FURTHER EAST, OVER SOUTHERN MANITOBA AND THE RED RIVER VALLEY,
CONSIDERABLE UNCERTAINTY REMAINS IN THE LOCATION OF THE RAIN/SNOW
TRANSITION. BEST BET FOR HEAVY SNOW WILL BE THROUGH THE INTERLAKE
TOWARDS THE ONTARIO BORDER. FOR THE CITY OF WINNIPEG, TEMPERATURES
LOOK TO REMAIN IN THE 0 TO +3 RANGE FOR MUCH OF THE EVENT, WHICH
WOULD LIMIT MAJOR ACCUMULATING SNOWFALL. STILL, STRONG CONVECTIVE
ELEMENTS TO THIS SYSTEM COULD RESULT IN RAPID BURSTS OF HEAVY SNOW AT
TIMES.
ADDITIONALLY, AS SPRINGTIME IS ON THE DOORSTEP THEORETICALLY, WITHIN
THE WARM SECTOR, THERE IS A NARROW FINGER 250 J/KG OF CAPE AND 40 TO
50 KT OF 0-6KM BULK SHEAR. ANY UPDRAFTS THAT ARE ABLE TO FORM ALONG
THE WARM SECTOR TROUGH WILL LIKELY GET SHEARED OFF, BUT SOME STRIKES
CERTAINLY ARE POSSIBLE.
A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR THE WINTER WEATHER.
THAT MAY BE ENOUGH TO COVER THE EVENT, BUT IT MAY REQUIRE UPGRADING
TO A SNOWFALL WARNING. IT WILL LIKELY BE EXTENDED EASTWARD THROUGH
MANITOBA AS WELL, BUT THAT IS IN THE OFFING. LATEST THINKING AS OF
MONDAY MORNING, WILL BE THAT A SWATH OF SNOWFALL WARNINGS WILL LIKELY
BE REQUIRED ACROSS CENTRAL SASKATCHEWAN INTO THE PARKLANDS OF
MANITOBA AT THE VERY LEAST. BEYOND THAT, FURTHER SOUTH AND EAST,
TRENDS IN MODEL RUNS WILL CONTINUE TO BE MONITORED FOR POSSIBLE
EASTWARD EXPANSION OF SNOWFALL WARNINGS AS THE EVENT NEARS.
NWT...FORT LIARD WILL BE CLIPPED BY OUR CLIPPER, WITH GUIDANCE FAIRLY
CONSISTENTLY SHOWING 5 TO 10 CM OF SNOW FOR THE TOWN TONIGHT.
OTHERWISE NO SIGNIFICANT WEATHER UNDER A RIDGE.
NUNAVUT...A WEAK SHORTWAVE PASSING OVER THE KIVALLIQ EARLY THIS
MORNING IS INTRODUCING SOME FRESH SNOWFALL TO MANY OF THE TOWNSITES.
RANKIN INLET OVERPERFORMED IN BLOWING SNOW YESTERDAY WITH NO FRESH
SNOWFALL, AND THE REGION WILL BE IN THE SAME TODAY AS THEY WERE
YESTERDAY. ADDITIONALLY, ACCORDING TO CAPS GUIDANCE, THIS MORNING,
ALL SITES WILL BE EXHIBITING AN OVERSATURATION DUE TO ICE AT THE TOP
OF THE MIXING LAYER IN ADDITION TO THE RECENT FRESH SNOWFALL.
WITH THE SAME 40G60 WINDS, INCLUDING 50G70 AT BAKER LAKE, BLIZZARD
CONDTIONS ARE EXPECTED TO DEVELP AT ALL KIVALLIQ TOWNSITES, SAVE FOR
CHESTERFIELD INLET, WHICH IS A BIT MORE SHELTERED. BLIZZARD WARNINGS
WENT OUT WITH YESTERDAY AFTERNOONS FORECAST AND WILL BE CONTINUED BY
THE NIGHT SHIFT. ADDITIONAL BLOWING SNOW/BLIZZARD CONCERNS WILL
RE-DEVELOP ON WEDNESDAY FOR THE KITIKMEOT AND KIVALLIQ AS ANOTHER
SHORTWAVE/COMPACT LOW DROPS SOUTHWARD OUT OF THE HIGH ARCTIC,
ALTHOUGH TEMPERATURES WILL BE MILDER WITH THIS SYSTEM.
END/STAMMERS/CARLSEN/STAUNTON
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