980
FXUS63 KILX 171145
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
545 AM CST SUN NOV 17 2024
KEY MESSAGES
- SHOWERS WILL RETURN TO CENTRAL ILLINOIS TONIGHT INTO MONDAY. A
FEW THUNDERSTORMS WILL BE POSSIBLE MONDAY EVENING: HOWEVER,
SEVERE WEATHER IS NOT EXPECTED.
- SOUTHWESTERLY WINDS WILL INCREASE LATE MONDAY AFTERNOON THROUGH
MONDAY NIGHT...WITH GUSTS REACHING 30-40MPH.
- AFTER AN EXTENDED PERIOD OF ABOVE NORMAL TEMPERATURES, MUCH
COOLER CONDITIONS WILL BE ON TAP FOR THE MIDDLE AND END OF THE
WEEK.
SHORT TERM
(TODAY THROUGH MONDAY)
ISSUED AT 354 AM CST SUN NOV 17 2024
A COLD FRONT CURRENTLY EXTENDING FROM NORTHERN WISCONSIN INTO
CENTRAL IOWA WILL SAG SLOWLY SOUTHEASTWARD TODAY...EVENTUALLY
BECOMING PARALLEL WITH THE UPPER FLOW AND STALLING JUST N/NW OF
THE KILX CWA. A BAND OF MID-LEVEL CLOUDINESS/WEAK RADAR ECHOES
ACCOMPANIES THE FRONT: HOWEVER, HAVE NOT SEEN ANY UPSTREAM OBS
REPORTING RAIN REACHING THE SURFACE. 00Z KILX UPPER AIR SOUNDING
SHOWED VERY DRY SUB-CLOUD LAYER AIR...WITH 850MB RH VALUES
DROPPING TO A BONE-DRY 2%. MOST CAMS GENERALLY INDICATE A
CONTINUATION OF VERY WEAK RADAR ECHOES ALONG/AHEAD OF THE FRONT,
BUT AM SKEPTICAL OF ANY MEASURABLE PRECIP REACHING THE SURFACE.
AS A RESULT, HAVE CARRIED JUST SCATTERED SPRINKLES ALONG/NORTH OF
I-72 THROUGH THE MORNING. BY LATE AFTERNOON, A SUBTLE SHORT-WAVE
TROUGH INTERACTING WITH THE BOUNDARY MAY TRIGGER SLIGHTLY MORE
SIGNIFICANT PRECIP ALONG THE FRONT NORTH OF A RUSHVILLE TO EL PASO
LINE WHERE SLIGHT CHANCE POPS FOR SHOWERS ARE WARRANTED. THANKS
TO S/SW WINDS AHEAD OF THE BOUNDARY, TEMPERATURES WILL BE A FEW
DEGREES WARMER THAN YESTERDAY...WITH HIGHS MOSTLY TOPPING OUT IN
THE LOWER 60S.
AS LOW PRESSURE DEEPENS OVER TEXAS AND DEEP-LAYER MOISTURE
ADVECTION FROM THE GULF OF MEXICO INCREASES, SHOWERS WILL DEVELOP
UPSTREAM ACROSS THE OZARKS DURING THE EVENING...THEN LIFT
NORTHWARD INTO PORTIONS OF CENTRAL ILLINOIS OVERNIGHT. BASED ON
MODEL CONSENSUS, HAVE MAINTAINED JUST SLIGHT CHANCE POPS THIS
EVENING, THEN HAVE INCREASED TO HIGH CHANCE/LIKELY ALONG/SOUTHWEST
OF A CANTON...TO DECATUR...TO EFFINGHAM LINE TOWARD DAWN MONDAY.
THE TEXAS LOW WILL CONTINUE TO DEEPEN AS IT TRACKS INTO KANSAS
DURING THE DAY MONDAY, PULLING A WARM FRONT NORTHWARD INTO CENTRAL
ILLINOIS. A BAND OF WAA PRECIP WILL SPILL INTO THE AREA FROM THE
SOUTH BY MORNING, THEN WILL LIFT NORTH OF THE I-74 CORRIDOR BY
LATE AFTERNOON. ONCE THE FRONT PASSES, SOUTHWESTERLY WINDS WILL
INCREASE MARKEDLY...WITH FORECAST SOUNDINGS AND NUMERIC GUIDANCE
INDICATE GUSTS REACHING 30-40MPH BY LATE AFTERNOON INTO MONDAY
NIGHT. THANKS TO STRONG WAA, AFTERNOON HIGHS WILL RISE INTO THE
LOWER TO MIDDLE 60S.
AS HAS BEEN ADVERTISED BY THE PAST SEVERAL MODEL RUNS, A BAND OF
CONVECTION WILL DEVELOP ALONG AN ADVANCING OCCLUDED FRONT AS IT
PUSHES INTO CENTRAL ILLINOIS FROM THE W/SW MONDAY NIGHT. MODELS
CONTINUE TO SHOW MODEST INSTABILITY PARAMETERS, SO HAVE OPTED TO
MENTION ISOLATED THUNDER AS THE SHOWERS ARRIVE.
BARNES
LONG TERM
(TUESDAY THROUGH SATURDAY)
ISSUED AT 354 AM CST SUN NOV 17 2024
ONCE THE FRONT PASSES, BREEZY AND MILD CONDITIONS WILL PREVAIL ON
TUESDAY WITH HIGHS ONCE AGAIN REACHING THE 60S. AS A SHORT-WAVE
TROUGH OVER ALBERTA/SASKATCHEWAN DROPS SOUTHEASTWARD AND PHASES
WITH A WAVE OVER THE UPPER MIDWEST, A LARGE CUT-OFF UPPER LOW WILL
FORM OVER THE GREAT LAKES/OHIO RIVER VALLEY BY THE END OF THE
WEEK. PLENTY OF QUESTIONS REMAIN REGARDING THE EXACT EVOLUTION OF
THIS PROCESS AND WHETHER ANY WINTRY PRECIP WILL OCCUR ACROSS
CENTRAL ILLINOIS. THE 00Z NOV 17 GFS NOW SHOWS A MOSTLY DRY
SOLUTION, WITH SURFACE LOW PRESSURE AND ANY ASSOCIATED PRECIP
REMAINING TO THE E/NE OF THE AREA. THE ECMWF/GEM BOTH SHOW THE
UPPER LOW DIGGING FURTHER SOUTH, WITH THE ATTENDANT SURFACE LOW
PIVOTING CLOSE ENOUGH TO TRIGGER PRECIP ACROSS AT LEAST PARTS OF
THE KILX CWA WEDNESDAY INTO THURSDAY. GIVEN THE HIGH DEGREE OF
UNCERTAINTY, HAVE OPTED TO MAINTAIN POPS THROUGH THE PERIOD MORE
IN LINE WITH THE ECMWF/GEM CONSENSUS. THINK THE ATMOSPHERIC
PROFILE WILL GENERALLY STAY WARM ENOUGH FOR RAIN, BUT WILL NEED TO
KEEP AN EYE ON THE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING TIME
FRAME WHEN THINGS MAY COOL JUST ENOUGH TO CREATE A RAIN/SNOW MIX.
MAIN WEATHER STORY WILL BE THE WINDY AND MUCH COOLER CONDITIONS.
HIGHS WILL DROP INTO THE LOWER 40S BY THURSDAY, AND WITH WINDS
GUSTING 30-35MPH, WIND-CHILL VALUES WILL HOVER IN THE UPPER 20S
AND LOWER 30S FOR MUCH OF THE DAY. AFTER THAT, CHILLY AND DRY
CONDITIONS WILL BE ON TAP FOR FRIDAY INTO NEXT WEEKEND.
BARNES
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 545 AM CST SUN NOV 17 2024
VFR CONDITIONS WILL PREVAIL AT THE CENTRAL ILLINOIS TERMINALS
THROUGH THIS EVENING BEFORE CEILINGS LOWER TO MVFR AND SCATTERED
SHOWERS DEVELOP OVERNIGHT. LATEST HRRR/RAP GUIDANCE SUGGESTS
CEILINGS BECOMING MVFR AT THE I-72 TERMINALS BY AROUND 05Z, WITH
VFR PERSISTING FURTHER NORTH AT KPIA/KBMI THROUGH 12Z MON. HAVE
INTRODUCED PREDOMINANT SHOWERS AT KSPI/KDEC AFTER 10Z AND HAVE
GONE WITH PROB30 FOR SHOWERS BETWEEN 09Z AND 12Z AT KCMI AND KBMI.
WINDS WILL INITIALLY BE S/SW AT 5-10KT, THEN WILL BACK TO E/SE AT
5-10KT LATE TONIGHT AHEAD OF AN APPROACHING WARM FRONT.
BARNES
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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