005
FXUS63 KILX 150933
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
333 AM CST FRI NOV 15 2024
KEY MESSAGES
- THE NEXT CHANCE FOR RAIN WILL ARRIVE SUNDAY NIGHT INTO MONDAY
AS A STORM SYSTEM APPROACHES FROM THE SOUTHWEST.
- TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY ABOVE NORMAL FOR THE
NEXT SEVERAL DAYS: HOWEVER, ALL INDICATIONS SUGGEST SHARPLY
COLDER CONDITIONS BY THE MIDDLE AND END OF NEXT WEEK.
SHORT TERM
(TODAY THROUGH SATURDAY)
ISSUED AT 333 AM CST FRI NOV 15 2024
08Z/2AM IR SATELLITE IMAGERY SHOWS OVERCAST CONDITIONS ACROSS MUCH
OF CENTRAL ILLINOIS...WITH THE BACK EDGE OF THE CLOUD COVER ALONG
A GALESBURG TO JACKSONVILLE LINE. THE CLEARING HAS BEEN INCHING
EASTWARD FOR THE PAST SEVERAL HOURS: HOWEVER, DO NOT THINK IT WILL
MAKE MUCH FURTHER PROGRESS BEFORE SUNRISE. WHERE SKIES HAVE CLEARED
NEAR THE MISSISSIPPI RIVER, DENSE FOG HAS DEVELOPED...WHICH WILL
LIFT INTO A LOW OVERCAST AFTER THE SUN COMES UP. END RESULT WILL
BE A CONTINUATION OF CLOUDY SKIES ACROSS THE KILX CWA BEFORE THE
BACK EDGE OF THE CLOUD SHIELD BEGINS TO DISSIPATE TOWARD MIDDAY.
WHILE COARSER MODELS SUCH AS THE GFS SUGGEST CLEARING WILL ADVANCE
STEADILY EASTWARD TO THE I-57 CORRIDOR DURING THE AFTERNOON, HIGHER
RESOLUTION MODELS SUCH AS THE HRRR/RAP ARE MUCH SLOWER WITH THE
CLEARING. WITH HIGH PRESSURE DIRECTLY OVERHEAD, NO APPRECIABLE DRY
ADVECTION FROM THE W/SW, AND THE LOW NOVEMBER SUN ANGLE...THINK
THE MORE PESSIMISTIC SOLUTIONS ARE PRUDENT. HAVE THEREFORE BROUGHT
PARTIAL CLEARING AS FAR EAST AS A LACON...TO LINCOLN...TO
TAYLORVILLE LINE THIS AFTERNOON...WITH SKIES REMAINING CLOUDY
FURTHER EAST. HIGH TEMPERATURES WILL TOP OUT NEAR SEASONAL NORMALS
IN THE LOWER TO MIDDLE 50S.
AS THE HIGH PRESSURE AXIS SHIFTS INTO THE OHIO RIVER VALLEY, A
LIGHT SE RETURN FLOW WILL DEVELOP LATE TONIGHT. THIS WILL PUSH THE
LOW CLOUDS BACK W/NW ACROSS THE ENTIRE CWA. GIVEN THE EXPECTED
CLOUD COVER, HAVE GONE AT OR ABOVE THE WARMEST NUMERIC GUIDANCE
FOR OVERNIGHT LOWS AS READINGS HOVER IN THE LOWER 40S. ONCE THE
HIGH MOVES FURTHER AWAY, THE PRESSURE GRADIENT WILL TIGHTEN AND
BOUNDARY LAYER FLOW WILL VEER MORE SOUTHERLY ON SATURDAY. THIS
WILL EVENTUALLY PUSH THE CLOUDS OUT OF THE AREA BY AFTERNOON AND
HELP BOOST HIGHS INTO THE UPPER 50S TO AROUND 60 DEGREES.
BARNES
LONG TERM
(SUNDAY THROUGH THURSDAY)
ISSUED AT 333 AM CST FRI NOV 15 2024
A VIGOROUS SHORT-WAVE TROUGH EVIDENT ON LATEST WATER VAPOR IMAGERY
ALONG THE WEST COAST WILL BE THE NEXT WEATHER-MAKER ACROSS CENTRAL
ILLINOIS. A PIECE OF ENERGY FROM THE WAVE WILL DIG SOUTHWARD AND
FORM A CLOSED LOW OVER THE DESERT SOUTHWEST ON SATURDAY. MEANWHILE
THE REMAINDER OF THE WAVE WILL QUICKLY LIFT E/NE INTO THE UPPER
MIDWEST. AS THE NORTHERN STREAM FEATURE APPROACHES, IT WILL PUSH A
WEAK COLD FRONT TOWARD CENTRAL ILLINOIS SATURDAY NIGHT INTO
SUNDAY. DEEP-LAYER MOISTURE WILL BE MINIMAL ALONG/AHEAD OF THE
BOUNDARY, SO OTHER THAN PERHAPS A STRAY SHOWER ALONG/NORTH OF A
MACOMB TO MINONK LINE...LITTLE OTHER SENSIBLE WEATHER WILL BE
OBSERVED. THANKS TO PARTIAL SUNSHINE AND LIGHT SW FLOW AHEAD OF
THE FRONT, HIGHS ON SUNDAY WILL CLIMB INTO THE LOWER TO MIDDLE
60S.
AS THE DESERT SOUTHWEST UPPER LOW GRADUALLY PIVOTS NORTHEASTWARD,
IT WILL INTERCEPT RICHER GULF OF MEXICO MOISTURE AND WILL BRING A
MUCH BETTER CHANCE FOR RAIN BY SUNDAY NIGHT INTO MONDAY. AN
INITIAL SURGE OF WAA SHOWERS WILL OCCUR SUNDAY NIGHT...FOLLOWED
BY WINDY AND WARM CONDITIONS DURING THE DAY MONDAY. NBM GUIDANCE
INDICATES S/SW WIND GUSTS POTENTIALLY INCREASING TO 30-35MPH BY
LATE AFTERNOON AND EVENING. AS THE SYSTEM OCCLUDES AND LIFTS
ACROSS KANSAS AND IOWA, THE TRAILING FRONTAL BOUNDARY WILL SWING
INTO CENTRAL ILLINOIS MONDAY EVENING. GFS SHOWS A NARROW BAND OF
INSTABILITY WITH MUCAPE VALUES OF 100-200J/KG. HAVE THEREFORE
ADDED THUNDER MENTION AS THE FRONT PASSES.
ANY SHOWERS/THUNDER WILL COME TO AN END LATE MONDAY NIGHT,
FOLLOWED BY A MILD AND DRY DAY ON TUESDAY. AFTER THAT, FORECAST
CONFIDENCE DECREASES SOMEWHAT AS MODELS TRY TO FIGURE OUT HOW TO
PHASE A SEPARATE UPPER LOW DROPPING SOUTHEASTWARD OUT OF
ALBERTA/SASKATCHEWAN WITH THE LOW THAT JUST PASSED ILLINOIS TO THE
NORTHWEST. THE GFS/GEM/ECMWF ALL PHASE THE TWO SYSTEMS INTO A DEEP
UPPER LOW OVER THE GREAT LAKES/OHIO RIVER VALLEY BY THE END OF THE
WEEK. WHILE THE BASIC PROCESS IS CERTAIN, THE EXACT TIMING AND
DETAILS HAVE NOT YET BEEN ADEQUATELY RESOLVED. WILL NEED TO KEEP A
CLOSE EYE ON HOW QUICKLY THE PHASING OCCURS AND WHERE ANY
ATTENDANT SURFACE LOW DEVELOPS. AT THIS POINT, WILL CONTINUE TO
ADVERTISE MUCH COOLER CONDITIONS WITH SCATTERED SHOWERS WEDNESDAY
INTO THURSDAY. HIGHS WILL DROP INTO THE LOWER TO MIDDLE 40S BY
THURSDAY WHILE BRISK N/NW WINDS CREATE WIND-CHILLS IN THE 30S.
WHILE THE ATMOSPHERE WILL LIKELY REMAIN WARM ENOUGH FOR RAIN, THE
POTENTIAL EXISTS FOR THE FIRST SNOW FLURRIES OF THE SEASON.
BARNES
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1027 PM CST THU NOV 14 2024
MOISTURE TRAPPED BELOW AN INVERSION ALOFT WILL KEEP A LAYER OF LOW
CLOUD COVER ENTRENCHED OVER CENTRAL IL MOST IF NOT ALL OF THE NEXT
24 HOURS. WITH HIGH PRESSURE SHIFTING OVER THE AREA FRIDAY
AFTERNOON, WE COULD SEE A THINNING OF THE CLOUD LAYER, AND
POTENTIALLY SOME BREAKING UP OF THE LAYER, HOWEVER MOST PHYSICAL
MODELS KEEP THE LAYER INTACT THROUGH 00Z SATURDAY, ESPECIALLY IN
EASTERN PORTIONS OF THE STATE, WITH STATISTICAL GUIDANCE
CONFLICTING WITH THIS SCENARIO TO A LARGE DEGREE, AND BREAKING UP
AND LIFTING THE CLOUD COVER BEFORE 18Z. HAVE GONE WITH THE MORE
PESSIMISTIC PHYSICAL MODEL IDEA, MORE TYPICAL THIS TIME OF YEAR.
THEREFORE, HAVE KEPT MVFR THROUGH 00Z EAST OF KPIA-KSPI, WITH VFR
AT KPIA-KSPI BY 21Z. ALSO INCLUDED PERIODS OF IFR CIGS THROUGH 15Z
AS GUIDANCE POINTS TO A GRADUAL LOWERING OF CIGS AND SOME THIN FOG
OVERNIGHT. WINDS NW 4-8 KTS OVERNIGHT, BECOMING LIGHT AND
VARIABLE BY 21Z.
37
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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