266
FXUS63 KARX 251736
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1136 AM CST WED DEC 25 2024
KEY MESSAGES
- ABOVE AVERAGE TEMPERATURES PERSIST WELL INTO NEXT WEEK WITH
HIGHS FRIDAY TO SUNDAY RUNNING 10 TO 15 DEGREES ABOVE NORMAL
IN THE LOW TO EVEN MID 40S.
- INCREASING SIGNAL FOR FREEZING DRIZZLE DEVELOPING TONIGHT,
TRANSITIONING TO DRIZZLE AS TEMPERATURES CLIMB ABOVE FREEZING
THROUGH THE MORNING ON THURSDAY. UNTREATED ROADWAYS MAY BECOME
SLICK FOR THE THURSDAY MORNING COMMUTE.
- WET WEATHER FOR THURSDAY THROUGH SATURDAY WITH THE HEAVIEST
RAINFALL COMING ON FRIDAY.
DISCUSSION
ISSUED AT 310 AM CST WED DEC 25 2024
'TWAS THE NIGHT BEFORE CHRISTMAS AND AT THE WEATHER BUREAU,
SKY GRIDS FOR TODAY WERE BEING ASSIGNED 1 0 0.
FOR HIGH PRESSURE RIDGING IS KEEPING FLOW WEAK
AND THE CHANCES FOR SUN ARE LOOKING QUITE BLEAK.
THOUGH OVER CENTRAL WI AN AREA OF TRANSIENT CLEARING,
HAS EARLY THIS MORNING LED TO FOG AND LOW TEMPERATURES VEERING.
BUT THE NEWS FOR TODAY ISN'T ALL BAD,
FOR MILD TEMPERATURES SHOULD MAKE SOME FOLKS QUITE GLAD.
MOISTURE LIFTS NORTH TONIGHT, THIS MUCH IS CERTAIN.
BUT THE DRIZZLE POTENTIAL HIDES BEHIND A THIN CURTAIN.
NEARLY 1-KM IN DEPTH BOUNDARY-LAYER MOISTURE WILL BE,
ROUGHLY THE THRESHOLD FOR DRIZZLE WE NEED.
WEAK ISENTROPIC ASCENT AT 280K SHOULD EXIST,
SO COLLISION COALESCENCE CANNOT BE DISMISSED.
ATTENTION THEN TURNS TO WET BULBS FLIRTING WITH FREEZING,
SOMETHING EVERY FORECASTER WILL FIND VERY DISPLEASING.
A DEGREE OR TWO DIFFERENCE CAN CHANGE THINGS QUITE QUICK,
FROM SIMPLE LIGHT DRIZZLE TO MAKING ROADS SLICK.
NO THIS INDEED IS NOT VERY NICE,
THE HREF HAS A 30-50 PERCENT PROBABILITY FOR A GLAZE OF ICE.
THE GOOD NEWS IS WARMER AIR IS ON THE WAY,
AND BY THURSDAY MIDDAY THIS THREAT MELTS AWAY.
THE LATE WEEK PATTERN FEATURES MANY AN AMPLIFIED WAVE,
THE NEXT OF WHICH EJECTS NORTHWARD AND ARRIVES EARLY FRIDAY.
THIS WILL BRING OUR BEST SHOT OF ACCUMULATING RAIN,
WHICH MAKES OUR SNOWPACK TOUGH TO MAINTAIN.
NEARLY 1/2 AN INCH OF RAIN WE MAY RECEIVE,
WHICH 10-20% OF THE ENSEMBLE MEMBERS HAVE UP THEIR SLEEVE.
ABOVE THE FREEZING MARK DEWPOINTS WILL RISE,
INCREASING THE RISK OF DENSE FOG IN THE SKIES.
CLIMBING INTO THE MID-40S HIGHS ON SATURDAY WILL WARM,
A SOLID 10 TO 15 DEGREES ABOVE THE NORM.
CONFIDENCE IN THIS WARM SPELL IS QUITE ALRIGHT,
WITH THE NBM TEMPERATURES CLUSTERED VERY TIGHT.
LOOKING TO NEXT WEEK TEMPERATURES START TO COOL DOWN,
BUT NO MAJOR COLD SNAPS WILL BE LURKING AROUND.
CONSENSUS IN THE PATTERN NEXT WEEK BEGINS TO DEGRADE,
BUT THERE DOESN'T SEEM TO BE ANYTHING OF WHICH TO BE AFRAID.
FROM WFO LA CROSSE WHERE THE LIGHTS ALWAYS BURN BRIGHT,
MERRY CHRISTMAS TO ALL, AND TO ALL A GOOD NIGHT.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1136 AM CST WED DEC 25 2024
LUCKILY ALL THE FLYING REINDEER HAVE COME AND GONE SINCE THE
AVIATION WEATHER IS NOT LOOKING GOOD MOVING FORWARD.
PERSISTENT STRATUS REMAINS IN PLACE WITH RELATIVELY LIGHT FLOW,
BUT AS SUCH FLOW INCREASES FROM THE SOUTH AHEAD OF WAVE OVER THE
ROCKIES, WE WILL SEE INCREASING THETA-E AND BROAD LIFT LEADING
TO MORE AND MORE LOW LEVEL SATURATION. THE MIX OF CEILINGS THIS
MORNING, RANGING FROM IFR IN THE WEST TO VFR ACROSS SOUTHERN
WISCONSIN, WILL DETERIORATE TONIGHT AND WORSEN GOING INTO THE
DAY THURSDAY. WHILE WE MAY ALSO SEE SOME DRIZZLE DEVELOP, FOR
AVIATION PURPOSES, THE MAIN STORY WILL BE LOW CEILINGS AND
LIKELY THICKENING FOG LEADING TO IFR TO LIFR CONDITIONS.
WHILE GUIDANCE IS NOT SUPER EXCITED ABOUT <1SM VISIBILITIES,
ONLY 40-50% CHANCE, FEELING IS THESE ARE UNDERPLAYING RISK SO
LOWERED IN TAFS. CONFIDENCE IS FAR HIGHER WITH CEILINGS AS MODEL
BLENDS ARE AT 90% OR HIGHER FOR IFR. EVEN RUDOLPH WOULD PASS ON
THOSE CONDITIONS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW
AVIATION...SHEA
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