834
FXUS63 KILX 150913
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
413 AM CDT THU MAY 15 2025
KEY MESSAGES
- NEAR-RECORD WARMTH IS FORECAST FOR TODAY.
- A RISK FOR SIGNIFICANT SEVERE WEATHER EXISTS THIS EVENING AND
AGAIN ON FRIDAY.
- A WET AND UNSETTLED PATTERN RETURNS FOR THE EARLY- TO MIDDLE-STAGES
OF NEXT WEEK.
DISCUSSION
(THROUGH NEXT THURSDAY)
ISSUED AT 1232 AM CDT THU MAY 15 2025
UNSEASONABLY HOT AND HUMID CONDITIONS WILL DEVELOP THIS AFTERNOON AS
AN UPPER- LEVEL DISTURBANCE LIFTS/PIVOTS INTO THE NORTHERN PLAINS
AND PULLS A WARM FRONT NORTHWARD ACROSS OUR AREA. TEMPERATURES
ACROSS THE WARM SECTOR ARE FORECAST TO ECLIPSE 90 DEGF IN A FEW
SPOTS WHILE DEWPOINTS SURGE INTO THE LOWER 70S AHEAD OF A BULGING
DRYLINE/PACIFIC-FRONT. AN UNSTABLE PBL WILL BECOME FURTHER
MODIFIED BY A STOUT EML AND STEEPENING MID-LEVEL LAPSE RATES TO
BUOY MLCAPE VALUES BETWEEN 3500-4500 J/KG. FOR PERSPECTIVE, OUR
RAOB ARCHIVES FOR THE MONTH OF MAY SUGGEST THESE VALUES HAVE ONLY
BEEN REACHED A HANDFUL OF TIMES SINCE THE 1950S. PRETTY RARE AIR.
IN ADDITION TO THE ROBUST THERMODYNAMICS IN PLACE, OUR KINEMATIC
SITUATION WILL ALSO RAMP UP THIS AFTERNOON AS A MID- LEVEL JET CORE
IMPINGES ON THE DRYLINE/PACIFIC-FRONT. THE NET EFFECT WILL BE
INCREASING DEEP-LAYER SHEAR (> 40 KTS) AND AN ELONGATED HODOGRAPH
SUPPORTIVE OF SUPERCELLS AND SPLITTING SUPERCELLS. A QUICK GLANCE
AT THE BULK SHEAR VECTORS WITH RESPECT TO THE DRYLINE FORCING
(ROUGHLY 60 DEG ANGLE) SUGGESTS DISCREET OR SEMI-DISCREET
SUPERCELLS CAPABLE OF PRODUCING ALL MODES OF SIGNIFICANT SEVERE
WEATHER. IF ANYTHING, RELATIVELY HIGH LCLS (> 1000M) COULD LIMIT
THE TORNADO POTENTIAL, PERHAPS LAYING THE GROUNDWORK FOR A
PROLIFIC HAIL EVENT INSTEAD.
THE 00Z HI-RES OUTPUT INDEED TRENDED MORE OMINOUS IN ITS
CONVECTIVE COVERAGE OVER CENTRAL IL FOR LATE THIS AFTERNOON INTO
EARLY EVENING. JUST ABOUT ALL CAM MEMBERS, SPARE THE FV3, NOW SHOW
SEMBLANCE OF CONVECTIVE INITIATION NEAR OR EAST OF THE IL RIVER
BETWEEN 21Z-23Z/4PM-6PM. ROBUST STORM MOTIONS (55 KTS FROM 240
DEG.) WILL LIMIT THE DWELL TIME OF ANY STORMS THAT DO DEVELOP
ACROSS OUR AREA, WITH CAMS GENERALLY SUPPORTING AN EXIT BETWEEN
01Z-03Z/8PM-10PM.
WHILE THE PROBABILITY FOR SEVERE WEATHER THIS EVENING HAS
GENERALLY INCREASED ACROSS PORTIONS OF CENTRAL AND EAST CENTRAL
ILLINOIS, A CASE CAN STILL BE MADE FOR NOTHING TO HAPPEN. RESIDUAL
CAPPING, DRY AIR ENTRAINMENT, AND THE POSSIBILITY THAT COOL
OUTFLOW EMANATING FROM A POTENTIAL MCS NEAR AND SOUTH OF I-70
THIS AFTERNOON (SEE 00Z, 06Z HRRR) ARE ALL WILD CARDS THAT COULD
LEAD TO A BUST DAY. FOR THESE REASONS, SPC'S DECISION TO NOT
EXPAND THE ENH RISK FURTHER SOUTH INTO OUR CWA SEEMS APPROPRIATE
FOR NOW.
FRIDAY'S SYNOPTIC SETUP THEN LOOKS EVEN MORE CONCERNING FOR THE
OCCURRENCE OF A SEVERE WEATHER OUTBREAK. SOME UNCERTAINTY STILL
EXISTS AS TO WHERE THE SURFACE BOUNDARY WILL BECOME RE-ORIENTED.
MORE OR LESS, THE DRYLINE/PACIFIC-FRONT WILL SAG SOUTHWARD AND
WASHOUT NEAR AND SOUTH OF I-70 OVERNIGHT, ONLY TO SHIFT BACK
NORTHWARD FRIDAY AFTERNOON AS SFC LOW PRESSURE LIFTS ACROSS THE
LOWER- OHIO RIVER VALLEY. THE POSITIONING OF THE SFC BOUNDARY ON
FRIDAY WILL BE AFFECTED BY ANY CONVECTIVE OUTFLOWS THAT MAY OR MAY
NOT DEVELOP THURSDAY NIGHT.
CONFIDENCE IN CONVECTIVE INITIATION ALONG THE BOUNDARY ON FRIDAY
IS HIGH, WITH THE FULL SUITE OF 00Z CAMS AS WELL AS NCAR'S
EXPERIMENTAL MPAS OUTPUT ABSOLUTELY ERUPTING OVER PORTIONS OF
CENTRAL AND SOUTHERN IL. IN ESSENCE, A SIMILAR CAPE/SHEAR PROFILE
EXISTS FOR FRIDAY BUT WITH LESS INHIBITION (CINH) TO OVERCOME.
STORM MODE WILL ONCE AGAIN FAVOR DISCREET SUPERCELLS CAPABLE OF
PRODUCING ALL SIG. SEVERE HAZARDS, THOUGH ONCE AGAIN, HIGH LCLS
MAY ULTIMATELY LIMIT THE TORNADO THREAT.
SATURDAY AND SUNDAY THEN LOOK CONVINCINGLY DRY AS A HIGH-
PRESSURE RIDGE BUILDS ACROSS THE PLAINS BEHIND THE DEPARTING
UPPER-LEVEL WAVE. TEMPERATURES WILL COME DOWN QUITE A BIT, CLOSER
TO THE SEASONAL AVERAGES (MID 70S). RAIN CHANCES THEN CREEP INTO
PORTIONS OF WESTERN/SOUTHERN IL BY MONDAY MORNING AS SHORTWAVE
ENERGY CRESTS THE TOP OF THE RIDGE AND SPAWNS NOCTURNAL PRECIP
SOMEWHERE ACROSS THE MID- TO LOWER- MISSISSIPPI VALLEY. A SIMILAR
DEAL COULD UNFOLD TUESDAY MORNING. THE BETTER PRECIP SIGNAL
ARRIVES TUESDAY EVENING AS YET ANOTHER UPPER TROUGH LIFTS ACROSS
THE CENTRAL US AND PUSHES A COLD FRONT ACROSS THE AREA. THE
ANALOGS (CIPS) AND VARIOUS ML TOOLS CONTINUE TO HIGHLIGHT TUESDAY
EVENING FOR ADDITIONAL SEVERE WEATHER POTENTIAL.
THE PATTERN THEN REMAINS WET AND UNSETTLED THROUGH THE MIDDLE OF
NEXT WEEK AS THE UPPER TROUGH CUTS OFF FROM THE MAIN BELT OF
WESTERLIES. DAILY TEMPERATURES COULD POTENTIALLY FALL BELOW
SEASONAL AVERAGES BY THEN.
MJA
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1213 AM CDT THU MAY 15 2025
A FEW SHOWERS WILL BE AROUND CENTRAL IL TONIGHT AS A WARM FRONT
LIFTS NORTH. LOW COVERAGE OF BKN MVFR CEILINGS ARE SHOWN BY
SEVERAL MODELS FROM 10-14Z, AND ADDED A TEMPO GROUP FOR THIS.
OTHERWISE DIURNAL CU WILL DOMINATE THE AREA TODAY. A DISTURBANCE
WILL SPARK ISOLATED TSRA LATE AFTERNOON/EARLY EVENING,
PARTICULARLY NEAR AND EAST OF I-55. DUE TO LOW COVERAGE INCLUDED A
PROB30 GROUP. IF A TERMINAL IS HIT BY A TSRA, BRIEF IFR AND DAMAGING
WINDS/LARGE HAIL ARE POSSIBLE. SSE WINDS WILL INCREASE AFTER
SUNRISE WITH 20-30 KT GUSTS COMMON, VEERING SW DURING THE
AFTERNOON. GUSTS SHOULD DIMINISH BETWEEN 00-02Z.
25
CLIMATE
ISSUED AT 727 PM CDT WED MAY 14 2025
RECORD TEMPERATURES FOR THURSDAY AND FRIDAY:
LOCATION THU RECORD THU RECORD FRI RECORD
. HIGH WARM LOW HIGH
============= ========== ========== ==========
BLOOMINGTON 94/1894 70/1962 92/1900
CHAMPAIGN 90/2001 66/1962 92/2001
CHARLESTON 92/2001 69/2013 94/2001
DECATUR 94/1894 68/1968 92/2001
JACKSONVILLE 91/2013 68/1962 90/2001
LINCOLN 90/1987 65/2013 92/2001
OLNEY 91/2018 69/1962 91/2001
PEORIA 89/1911 67/1998 90/2001
SPRINGFIELD 91/1962 69/1962 93/2001
GEELHART
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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