915
FXUS63 KILX 221932
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
232 PM CDT TUE APR 22 2025
KEY MESSAGES
- THERE IS A MARGINAL RISK (LEVEL 1 OF 5) FOR SEVERE THUNDERSTORMS
LATE THIS AFTERNOON INTO THE EVENING NORTH OF A RUSHVILLE TO
BLOOMINGTON LINE. THE PRIMARY HAZARDS ARE HAIL AND DAMAGING WIND
GUSTS (5% CHANCE WITHIN 25 MILES).
- ABOVE NORMAL TEMPERATURES WILL PREVAIL THROUGH THE REMAINDER OF
THE WEEK. EXPECT AFTERNOON HIGHS AROUND 80 DEGREES WEDNESDAY AND
THURSDAY.
DISCUSSION
ISSUED AT 228 PM CDT TUE APR 22 2025
THIS AFTERNOON, A BROAD FRONTAL ZONE LIES FROM SOUTHEASTERN
WISCONSIN BACK ACROSS NORTHERN ILLINOIS AND INTO WEST CENTRAL
ILLINOIS. NEAR THE FRONT, TEMPS IN THE LOWER TO MID 70S AND DEW
POINTS POOLING IN THE MID 50S ARE CONTRIBUTING TO MLCAPE OF 1000-
1250 J/KG WITH LITTLE CONVECTIVE INHIBITION. SCATTERED SHOWERS AND
STORMS ARE EXPECTED TO CONTINUE TO PERCOLATE WITHIN THE FRONTAL
TROUGH THROUGH LATE THIS EVENING. A FEW OF THE STRONGER STORMS
COULD BECOME SEVERE WITH DAMAGING WIND GUSTS AND ONE INCH HAIL THE
PRIMARY CONCERNS.
QUASI-STATIONARY FRONTAL BOUNDARY WILL GRADUALLY BEGIN TO LIFT
BACK NORTH WEDNESDAY TO NEAR THE IL/WI STATE LINE AND WILL SERVE
AS THE FOCUS FOR ADDITIONAL SHOWERS AND STORMS. WEAK INSTABILITY
NEAR THE FRONT WILL TAPER OFF TO LESS THAN 100 J/KG BY THE I-74
CORRIDOR. LACK OF INSTABILITY FURTHER SOUTH AND WELL DISPLACED
FROM THE FORCING, CENTRAL ILLINOIS SHOULD BE DRY THROUGH THE
AFTERNOON AND EVENING. TEMPERATURES WILL WARM TO AROUND 80 DEGREES
AREA-WIDE WEDNESDAY AFTERNOON.
CONDITIONS THURSDAY WILL BE SIMILAR TO WEDNESDAY WITH A DRY START
TO THE DAY AND TEMPERATURES WARMING TO AROUND 80 DEGREES. A
SHORTWAVE TROUGH LIFTING FROM THE CENTRAL PLAINS WILL CROSS THE
MID MISSISSIPPI VALLEY THURSDAY EVENING WITH ACCOMPANYING SHOWERS
AND STORMS APPROACHING FROM THE WEST. ANY CONVECTION WILL BE
OUTRUNNING THE STRONGER INSTABILITY TO OUR WEST SO SHOULD BE IN A
WEAKENING PHASE WITH A SEVERE THREAT NOT APPARENT.
MORE WIDESPREAD SHOWERS AND STORMS ARE EXPECTED FRIDAY AS SYNOPTIC
SCALE FORCING INCREASES ACROSS THE REGION. ALOFT, COUPLED JET
STREAKS WILL BE IN PLACE WITH THE NORTHERN STREAM OVER THE GREAT
LAKES AND THE SOUTHERN STREAM OVER THE SOUTHERN PLAINS. THE RIGHT
ENTRANCE REGION OF THE FORMER AND THE LEFT EXIT REGION OF THE
LATTER WILL BE LOCATED OVER THE MID MISSISSIPPI VALLEY AND MIDWEST
FRIDAY. IN ADDITION, ANOTHER SHORTWAVE TROUGH WILL DIG ACROSS THE
MID MISSISSIPPI VALLEY EARLY FRIDAY EVENING. WEAK INSTABILITY
WITH MLCAPE GENERALLY LESS THAN 500 J/KG AND SUBOPTIMAL DEEP LAYER
SHEAR OF 20-25KT WILL LIMIT ANY SEVERE THREAT WITH CONVECTION
FRIDAY AFTERNOON AND EVENING.
BEHIND FRIDAY'S DEPARTING WAVE, HIGH PRESSURE WILL BUILD SOUTH
FROM THE CANADIAN PRAIRIES ACROSS THE MIDWEST OVER THE WEEKEND.
TEMPS BRIEFLY MODERATE SATURDAY WITH HIGHS BACK DOWN IN THE MID TO
UPPER 60S IN THE NORTHERLY FLOW. RIDGE AXIS SHIFTS TO OUR EAST
SUNDAY ALLOWING TEMPS TO REBOUND BACK INTO THE 70S ON THE RETURN
OF SOUTHERLY FLOW. EXPECT THE WEEKEND TO BE DRY UNDER THE
INFLUENCE OF THE RIDGE.
MORE ACTIVE WEATHER RETURNS EARLY NEXT WEEK THOUGH DETAILS REMAIN
A BIT UNSURE AT THIS DISTANCE DUE TO DIFFERENCES IN THE STRENGTH
AND TIMING OF LOW PRESSURE LIFTING ACROSS THE UPPER MIDWEST. A
TRAILING COLD FRONT WILL EVENTUALLY PASS THROUGH CENTRAL ILLINOIS.
IF DIURNAL TIMING IS FAVORABLE WITH PASSAGE OF THIS SYSTEM, AND
GIVEN THE MAGNITUDE OF THE LOW AND FAVORABLE LOW LEVEL
TRAJECTORIES ALLOWING A RETURN OF GULF MOISTURE INTO THE REGION,
WOULDN'T RULE OUT A SEVERE WEATHER THREAT. NBM JOINT PROBABILITIES
FOR SBCAPE GREATER THAN 500 J/KG AND 30 KTS OF BULK SHEAR PEAK
AROUND 60 PERCENT FOR WESTERN PORTIONS OF THE AREA MONDAY EVENING
AND AGAIN AREA-WIDE TUESDAY AFTERNOON. TIMING DETAILS WILL HAVE TO
BE IRONED OUT IN THE UPCOMING DAYS AS THIS SYSTEM COMES INTO
BETTER FOCUS.
DEUBELBEISS
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1250 PM CDT TUE APR 22 2025
A COUPLE ILL-DEFINED FRONTAL BOUNDARIES SPRAWLED ACROSS IOWA AND
NORTHERN ILLINOIS TODAY HAVE RESULTED IN SCATTERED SHOWERS AND
THUNDERSTORMS, WHICH ARE EXPECTED TO DRIFT INTO OUR AREA AS THEY
PERCOLATE THIS AFTERNOON. LACK OF STRONG WINDS ALOFT AND MARGINAL
INSTABILITY SUGGEST THESE STORMS WILL BE RATHER CAPRICIOUS,
EVOLVING ALONG THEIR OWN OUTFLOW BOUNDARIES AND MOVING RELATIVELY
SLOWLY. IN ADDITION, AS INDIVIDUAL STORMS COLLAPSE, THEY'LL BE
CAPABLE OF GENERATING GUSTY OUTFLOW WINDS DUE TO DRY LOW LEVELS
AND HIGH CLOUD BASES AROUND FL060 TO FL080. THE TERMINAL OF
GREATEST CONCERN WILL BE PIA, WHILE BMI MAY ALSO BE IMPACTED THIS
EVENING.
IN THE WARM SECTOR AHEAD OF THESE STORMS, WINDS VEERING FROM
SOUTH-SOUTHEAST TO SOUTH-SOUTHWEST THIS AFTERNOON MAY GUST TO 20
KT OR HIGHER AT TIMES. VFR CONDITIONS WILL BE PREDOMINANT
EVERYWHERE, THOUGH IN ANY STORMS AT PIA AND BMI BRIEF VISIBILITY
DROPS INTO THE IFR CATEGORY MAY OCCUR. OVERNIGHT, WINDS WILL EASE
AND STORMS DISSIPATE, THOUGH LINGERING ISOLATED SHOWERS MAY LINGER
INTO WEDNESDAY MORNING.
BUMGARDNER
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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