267
FXUS63 KILX 201110
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
510 AM CST THU FEB 20 2025
KEY MESSAGES
- AN AGGRESSIVE WARMING TREND WILL TAKE SHAPE THIS WEEKEND WITH
TEMPERATURES SURGING WELL INTO THE 40S AND 50S BY EARLY NEXT
WEEK.
- AFTER A STRETCH OF DRY WEATHER, MULTIPLE CHANCES FOR LIGHT
PRECIPITATION RETURN BY THE MIDDLE OF NEXT WEEK. AT THIS TIME,
THE NEXT BEST CHANCE COMES WEDNESDAY (30-50% CHANCE) IN THE FORM
OF RAIN, PERHAPS TRANSITIONING TO SNOW WEDNESDAY NIGHT.
DISCUSSION
ISSUED AT 1248 AM CST THU FEB 20 2025
MID-LEVEL HEIGHTS WILL CONTINUE TO INCREASE ACROSS THE AREA
THROUGHOUT TODAY AS THE MAIN TROUGH DEPARTS TO OUR EAST. WITH THE
UPPER RIDGE AXIS AND ATTENDANT SURFACE HIGH BUILDING INTO THE
MISSISSIPPI VALLEY LATE TONIGHT, WE SHOULD BEGIN TO SEE A GREATER
PUSH OF WARM ADVECTION. THE NET EFFECT WILL BE PROGRESSIVELY
WARMER TEMPERATURES THROUGH THE REMAINDER OF THE WEEK ALONG WITH
DRY WEATHER AS THE RESIDUAL CONTINENTAL (HIGH PRESSURE) AIRMASS
LOITERS OVER THE REGION. LATEST NBM GUIDANCE PUSHES TEMPERATURES
INTO THE 30S ON SATURDAY; THE 40S ON SUNDAY; AND 50S BY MONDAY.
THIS SEEMS REASONABLE AS AN UPPER RIDGE AMPLIFIES OVER THE WESTERN
CONUS AND PUMPS PERSISTENT NORTHWEST/DOWNSLOPE/WARMING FLOW INTO
THE PLAINS.
WITH THE AO/NAO TRENDING POSITIVE OR AT LEAST NEUTRAL THROUGH
LATE FEBRUARY, AND WITH AN INCREASING SUN ANGLE, THINKING WE MAY
SEE OUR LAST SINGLE-DIGIT LOW OF THE WINTER TONIGHT. EVEN WITH A
BIT OF A COLDER SIGNAL RETURNING DURING THE FIRST WEEK OF MARCH,
GLOBAL ENSEMBLE MEAN TEMPERATURES APPEAR TO KEEP OVERNIGHT LOWS IN
THE 20S DURING THAT PERIOD. EVEN THE COLDER (25TH PERCENTILE)
TAIL OF GUIDANCE STRUGGLES TO SNIFF OVERNIGHT LOWS IN THE TEENS BY
THEN. THERE'S YOUR SILVER LINING ON THIS BITTERLY COLD DAY.
AS WE HEAD INTO NEXT WEEK, DRY AND MILD CONDITIONS SHOULD PERSIST
ON THE FRONT END. CHOPPY NORTHWEST FLOW WILL CHARACTERISTICALLY BRING
A PARADE OF COMPACT SHORTWAVES ACROSS THE MISSISSIPPI VALLEY
THROUGH THE MIDDLE OF THE WEEK. THE FIRST OF THESE WAVES DROPS
INTO THE REGION SUNDAY. WITH NORTHWEST FLOW STYMIEING MOISTURE
RETURN FROM THE GULF, THINKING THIS INITIAL WAVE PUSHES THROUGH
DRY. SAME DEAL WITH ADDITIONAL SHORTWAVE ENERGY RIPPLING THROUGH
ON MONDAY. A MORE ORGANIZED WAVE THEN COMES THROUGH LATE MONDAY
NIGHT INTO TUESDAY. THE MOISTURE PROFILE LOOKS MORE FAVORABLE FOR
LIGHT PRECIP, THOUGH WITH ITS PACIFIC ORIGINS, MIGHT BE DIFFICULT
FOR US TO MUSTER ANYTHING MORE THAN JUST A COUPLE HUNDREDTHS. THE
DEEPEST OF THE WAVES DIGS INTO OUR AREA BY WEDNESDAY, AND BY THAT
TIME, WE DO GET SOME GULF MOISTURE ADVECTING NORTHWARD AHEAD OF
IT. BOTH BLENDED (NBM) AND GLOBAL ENSEMBLE GUIDANCE CORRECTLY
IDENTIFIES THIS AS THE NEXT BEST CHANCE (30-50% PROBABILITY) FOR
WIDESPREAD PRECIP FOR CENTRAL ILLINOIS. THERMAL PROFILES SUPPORT
RAIN DURING THE DAY ON WEDNESDAY, THEN TRANSITIONING TO LIGHT SNOW
AS COLDER TEMPERATURES CRASH IN FROM THE NORTHWEST WEDNESDAY
NIGHT. AS OF RIGHT NOW, THERE IS ENOUGH VARIABILITY IN THE
TIMING/DEPTH OF THIS WAVE THAT THE MEAN KIND OF GETS WASHED OUT,
BUT GUIDANCE DOES OFFER A LOW PROBABILITY (15% CHANCE) FOR
ACCUMULATING SNOW.
MJA
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 509 AM CST THU FEB 20 2025
VFR CONDITIONS WILL PERSIST THROUGH THIS TAF PERIOD AS SKIES
REMAIN MOSTLY CLEAR BEHIND A DEPARTING UPPER-LEVEL TROUGH. WINDS
WILL MAINTAIN A NW COMPONENT TODAY, BECOMING LIGHT AND VARIABLE
OVERNIGHT.
MJA
ILX WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR ILZ027>031-
036>038-040>044-047>056-061>063-066>068-071>073.
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