714
FXUS63 KARX 190002
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
602 PM CST SAT JAN 18 2025
KEY MESSAGES
- BITTER COLD TEMPERATURES ARE EXPECTED THROUGH THE WEEKEND AND
INTO EARLY NEXT WEEK. DANGEROUS WIND CHILLS OF -25 TO -35F ARE
EXPECTED NIGHTLY INTO TUESDAY, WITH A FEW LOCATIONS
POTENTIALLY DROPPING BELOW -35F TUESDAY MORNING.
- TEMPERATURES LOOK TO MODERATE BACK TOWARDS NORMAL MID TO LATE
WEEK WITH A CHANCE (AT LEAST 20 TO 30%) FOR LIGHT SNOW
WEDNESDAY AFTERNOON INTO THURSDAY.
DISCUSSION
ISSUED AT 132 PM CST SAT JAN 18 2025
COLD TEMPERATURES THROUGH EARLY NEXT WEEK
OUR WELL ADVERTISED COLD SNAP REMAINS ON TRACK FOR TONIGHT THROUGH
TUESDAY.
COLD FRONT WHICH PUSHED THROUGH THE FORECAST AREA YESTERDAY IS WELL
TO OUR SOUTHEAST WITH A BROAD SURFACE RIDGE, CENTERED IN THE WESTERN
CANADIAN PRAIRIES, BUILDING SOUTHEASTWARD THROUGH THE PLAINS AND
UPPER MIDWEST. A SECONDARY UPPER TROUGH IS SEEN ON WV SATELLITE TO
OUR NORTHWEST, WILL PASS SOUTHEAST LATE THIS AFTERNOON INTO THIS
EVENING, REINFORCING OUR TREND TOWARD COLDER TEMPERATURES. WITH
ADDITIONAL IMPULSES SEEN ACROSS MOST GUIDANCE MONDAY AFTERNOON AND
TUESDAY MORNING, EXPECT AN EXTENDED PERIOD OF HAZARDOUSLY COLD
CONDITIONS, PARTICULARLY DURING THE NIGHTTIME HOURS. HOWEVER, OF
NOTE IS THAT A DECENT AMOUNT OF CLOUD COVER LOOKS TO BE PRESENT
SATURDAY AND SUNDAY NIGHTS, SO HAVE STUCK WITH THE ALREADY PLENTY
COLD NBM GUIDANCE FOR LOWS BOTH OF THESE NIGHTS. AS FOR MONDAY
NIGHT, SKIES LOOK MORE LIKELY THAN NOT TO CLEAR, SO HAVE MOVED
TOWARD CONSENSUS MOS VALUES WHICH TEND TO DO VERY WELL WITH
RADIATIONAL COOLING NIGHTS.
PROBABILITY FOR IMPACTS REMAINS HIGH EACH NIGHT SATURDAY NIGHT
THROUGH MONDAY NIGHT. 18.12Z HREF PROBABILITIES SUGGEST A 70 TO 100
PERCENT CHANCE FOR WIND CHILLS TO DROP TO AT LEAST -25 TONIGHT.
LOOKING AHEAD, THE 18.00Z LREF INDICATES A 40 TO 100 AND 85 TO 100
PERCENT CHANCE TO REACH THE SAME THRESHOLD SUNDAY AND MONDAY NIGHTS
RESPECTIVELY, WITH THOSE RELATIVELY LOWER PROBABILITIES SUNDAY NIGHT
RESIDING IN NORTHEASTERN IOWA AND FAR SOUTHWESTERN WISCONSIN. AS FOR
REACHING -35, 18.12Z HREF SUGGESTS ABOUT AN 80 PERCENT CHANCE TO
BRIEFLY REACH THIS THRESHOLD AROUND ROCHESTER EARLY SUNDAY MORNING
BUT HAVE LOWER CONFIDENCE IN THIS OUTCOME GIVEN THE EXPECTED CLOUD
COVER. MONDAY NIGHT INTO TUESDAY MORNING LOOK TO BE OUR BEST SHOT AT
REACHING -35 GIVEN THE POTENTIAL FOR MOSTLY CLEAR SKIES AND A LIGHT
BREEZE, WITH AREAS NORTH OF A ROCHESTER TO WINONA TO TOMAH ARC
HAVING A 50-70% CHANCE PER THE 18.00Z LREF.
GIVEN THE ABOVE, HAVE KEPT HEADLINES STEADY WITH THIS UPDATE - A
COLD WEATHER ADVISORY ACROSS THE CWA TONIGHT INTO TOMORROW MORNING,
FOR ALL BUT NORTHEAST IOWA AND FAR SOUTHWESTERN WI SUNDAY NIGHT INTO
MONDAY MORNING. HAVE CONTINUED TO LEAVE MONDAY NIGHT INTO TUESDAY
MORNING WITHOUT A HEADLINE FOR NOW TO AVOID DOUBLE HEADLINES AND DUE
TO UNCERTAINTY ABOUT HOW FAR SOUTH IN THE CWA AN EXTREME COLD
WARNING WILL BE NEEDED.
MIDWEEK MODERATING TEMPERATURES, LIGHT SNOW POTENTIAL
HEIGHTS ALOFT WILL TEND TO RISE FOLLOWING TUESDAY MORNING'S UPPER
TROUGH, BRINGING RELATIVE RELIEF TO THE REGION WITH OVERNIGHT LOWS
FAVORED (80-95%) TO REMAIN ABOVE 0F STARTING WEDNESDAY NIGHT
WITH AFTERNOON HIGHS EVEN HAVING A 30 TO 50 PERCENT CHANCE PER
18.06Z NBM TO CLIMB TO FREEZING FRIDAY AFTERNOON SOUTHWEST OF
I-94. IN THE INTERIM, GOOD AGREEMENT ACROSS OPERATIONAL GUIDANCE
AND THEIR ENSEMBLES THAT AN UPPER TROUGH WILL SLIDE EAST OVER
THE REGION SOMETIME WEDNESDAY NIGHT INTO THURSDAY. WHILE LIFT
LOOKS TO BE MODEST, THERE SHOW BE ENOUGH MOISTURE IN THE COLUMN
- INCLUDING THE DGZ - TO PRODUCE A SMALL AMOUNT OF SNOW. NBM
CONTINUES TO STRUGGLE TO HANDLE MINOR SNOW AMOUNT EVENTS AND
GENERALLY INDICATES AROUND A 10 PERCENT CHANCE FOR SNOW WHILE
18.00Z LREF HAS A 60 TO 90 PERCENT CHANCE FOR AT LEAST A TENTH
OF AN INCH. HAVE THEREFORE MOVED TOWARD OTHER CONSENSUS BLENDS
TO INTRODUCE A MENTION OF LIGHT SNOW WEDNESDAY NIGHT INTO
THURSDAY.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 552 PM CST SAT JAN 18 2025
CONTINUE TO MONITOR MVFR TRENDS. MAINLY MID AND HIGH LEVEL
CLOUDS OVER THE REGION FL100-250. UPSTREAM ACROSS PARTS OF
CENTRAL MINNESOTA, THERE ARE PATCHY MVFR CONDITIONS FL015-030.
THE HREF HAS LOW LEVEL CLOUDINESS INCREASING ACROSS THE FORECAST
AREA, HOWEVER THERE ARE QUESTIONS RELATED TO COVERAGE. THE
RAP/HRRR/NAM SHOW VARIABLE AMOUNTS OF LOW CLOUDS AND HAVE IT IN
OVERCAST FOR OVER A THIN LAYER. THE SOUTHERN EDGE ON THE EDGE OF
THE SNOWFIELD HAS NOT PUSHED SOUTHWARD MUCH OVER THE LAST TWO
HOURS. DUE TO THE LOW CONFIDENCE IN COVERAGE, HELD OFF ON MVFR
CONDITIONS UNTIL AFTER THE NEXT SET OF TAFS WILL GO OUT. THE
HREF SHOWS THAT MVFR CONDITIONS SHOULD IMPROVE AFTER 15Z.
REINFORCING COLD AIR MOVES IN TONIGHT SHOULD CONTINUE TO KEEP
NORTHWEST WINDS ELEVATED MOSTLY 10 TO 20KTS WITH GUSTS 20 TO
30KTS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
SUNDAY FOR WIZ054-061.
COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
MONDAY FOR WIZ032>034-041>044-053-055.
COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 PM CST
MONDAY FOR WIZ017-029.
MN...COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
MONDAY FOR MNZ079-088-096.
COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 PM CST
MONDAY FOR MNZ086-087-094-095.
IA...COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
SUNDAY FOR IAZ008>011-018-019-029-030.
DISCUSSION...FERGUSON
AVIATION...ZAPOTOCNY
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