006
FXUS63 KLOT 232330
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
630 PM CDT WED APR 23 2025
KEY MESSAGES
- SHARP TEMPERATURE CONTRAST ACROSS THE REGION ON THURSDAY AS A
LAKE-ENHANCED FRONT PUSHES INTO THE REGION.
- SHOWER AND STORM CHANCES INCREASE THURSDAY NIGHT INTO FRIDAY
WITH THE NEXT WEATHER MAKER, ALTHOUGH THE SEVERE RISK APPEARS
LOW.
- THE STRETCH OF WARM WEATHER WILL CONTINUE (AWAY FROM THE LAKE),
PAUSING BRIEFLY ON SATURDAY BEFORE TEMPERATURES TURN EVEN
WARMER EARLY NEXT WEEK.
- STRONGER STORM SYSTEM SET TO ARRIVE EARLY NEXT WEEK, WITH SOME
THREAT FOR STRONG TO SEVERE STORMS IN THE REGION.
DISCUSSION
ISSUED AT 315 PM CDT WED APR 23 2025
THROUGH THURSDAY:
IN THE WAKE OF THIS MORNING'S CONVECTION, QUITE A CONTRAST HAS
SET UP ACROSS THE REGION, WITH TEMPERATURES IN THE MID AND UPPER
70S SOUTH OF I-80 WHERE INSOLATION HAS BEEN THE MOST
SIGNIFICANT. FARTHER TO THE NORTH, THE AIRMASS IS ONLY JUST NOW
STARTING TO RECOVER, WITH WINDS TURNING OUT OF THE SOUTH AND
SOUTHWEST AND AIR TEMPERATURES MEANDERING TOWARDS 70. LATEST
GUIDANCE SUGGESTS THAT CONVECTIVE INHIBITION--AT LEAST TO
SURFACE-BASED PARCELS--WILL REMAIN IN PLACE ACROSS MOST OF THE
REGION, EXCEPT PERHAPS WELL NORTH OF I-88 LATE THIS AFTERNOON.
IN THIS AREA AND TOWARDS THE WISCONSIN STATE LINE, CAN'T RULE
OUT A FEW SHOWERS OR STORMS DEVELOPING INTO THE EARLY EVENING,
AND HAVE MAINTAINED SOME SLIGHT CHANCES TO ACCOUNT FOR THIS.
TO THE SOUTH OF I-88, SOME ENHANCED VERTICAL GROWTH WITHIN A
CLOUD DECK WITH BASES NEAR 12 KFT SUGGEST A FEW HIGH-BASED
SPRINKLES/SHOWERS MAY ALSO DEVELOP THROUGH THE AFTERNOON AS THIS
ACTIVITY SHIFTS EASTWARD TOWARDS THE LAKE.
OTHERWISE, THE FOCUS FOR ANY ADDITIONAL SHOWERS AND STORMS
TONIGHT SHOULD CONTINUE TO INCREMENTALLY SHIFT FARTHER TO THE
WEST AND NORTH OF THE REGION AS THE MAIN RESERVOIR OF ELEVATED
INSTABILITY PIVOTS NORTHWESTWARD. BROAD/WEAK ISENTROPIC ASCENT
TONIGHT MAY PROVIDE ENOUGH IMPETUS FOR RENEWED ELEVATED
CONVECTIVE DEVELOPMENT, BUT AGAIN WITH THE MUCAPE AXIS MIGRATING
OUT OF THE REGION, HAVE PUSHED MENTIONABLE POPS OUT OF THE
FORECAST AREA.
THE MAIN STORY ON THURSDAY WILL BE A SHARP TEMPERATURE CONTRAST
ACROSS THE REGION AS A NOTABLE COLD FRONT DROPS DOWN THE LAKE.
WHILE THERE'S BEEN SOME SIGNIFICANT DISPARITY IN THE HANDLING OF
THE TIMING OF THIS FEATURE ACROSS THE GUIDANCE SUITE, GIVEN THE
FRONT'S SHALLOW NATURE AND LAKE TEMPERATURES STILL IN THE UPPER
40S/NEAR 50 DEGREES, SEEMS PRUDENT TO CONTINUE TO FOLLOW THE
FASTER GUIDANCE (WRFARW, ECMWF). LATEST HRRR HAS SPED UP
MARKEDLY AS WELL, WHICH LENDS SOME CONFIDENCE TO THIS.
TEMPERATURES WILL FALL SHARPLY WITH THE FRONT'S ARRIVAL NEAR THE
LAKE, AND WILL LIKELY REMAIN IN THE MID/UPPER 50S, WHILE INLAND
LOCALES SOUTH OF I-80 WILL ROCKET INTO THE UPPER 70S AND LOWER
80S. CAN'T ENTIRELY RULE OUT SOME MARINE FOG WITH THE FRONT TOO,
WHICH MIGHT BLEED INLAND, PARTICULARLY THURSDAY EVENING. AT
THIS TIME, CONFIDENCE IN FOG WAS A BIT TOO LOW TO INTRODUCE INTO
THE FORECAST, BUT IS SOMETHING WE'LL KEEP A CLOSE EYE ON.
THURSDAY NIGHT THROUGH WEDNESDAY:
OUR NEXT WEATHER MAKER WILL ARRIVE THURSDAY NIGHT INTO FRIDAY AS
A FAIRLY LOW AMPLITUDE MID-LEVEL WAVE PUSHES OVERHEAD. WHILE
SOME INITIAL WARM ADVECTION-DRIVEN SHOWERS AND STORMS WILL BE
POSSIBLE THURSDAY EVENING ACROSS OUR WEST, THE MAIN PUSH OF
DEEP LAYER MOISTURE AND ASCENT WON'T ARRIVE UNTIL LATE THURSDAY
EVENING AND OVERNIGHT. THE SEVERE WEATHER THREAT WILL BE LOW
DURING THIS PERIOD WITH LIMITED DEEP LAYER SHEAR, ALTHOUGH CAN'T
RULE OUT SOME SMALL HAIL. ADDITIONAL SHOWERS WILL LIKELY DEVELOP
THROUGH FRIDAY MORNING AS A REINFORCING COLD FRONT SHIFTS
SOUTHWARD ACROSS THE REGION. AS THIS OCCURS, THE MAIN
THUNDERSTORM THREAT AREA WILL COMMENSURATELY PUSH SOUTH OF I-80
DURING THE AFTERNOON. ALTOGETHER, THE SEVERE WEATHER THREAT ON
FRIDAY LOOKS LOW GIVEN A DEARTH OF INSTABILITY AND SHEAR.
COULDN'T RULE OUT A FEW FUNNEL CLOUDS MATERIALIZING IN THIS
SETUP WITH INCREASING NEAR-SURFACE VORTICITY ALONG THE FRONT,
PWATS RAPIDLY PUSHING THROUGH 1.5 INCHES, AND LIMITED BULK
SHEAR.
HIGH PRESSURE BUILDS INTO THE REGION OVER THE WEEKEND WITH
COOLER BUT TRANQUIL CONDITIONS. LOOKS LIKE SATURDAY NIGHT WILL
BE A COOL/CRISP ONE, WITH LOWS POTENTIALLY MEANDERING INTO THE
MID 30S IN OUR TYPICAL SHELTERED/COOL SPOTS.
HIGH PRESSURE MOVES EAST OF THE REGION EARLY NEXT WEEK, WITH
RETURN FLOW COMMENCING. THIS WILL PUMP MOISTURE AND INSTABILITY
RAPIDLY NORTHWARD ACROSS THE REGION AS A ROBUST WAVE EMBEDDED
WITHIN BROAD UPPER TROUGHING SLICES THROUGH THE UPPER MIDWEST
DURING THE MONDAY AFTERNOON - TUESDAY TIMEFRAME. INCREASING WIND
FIELDS NEAR THE SURFACE AND ALOFT SPELL SOME POTENTIAL FOR
STRONG TO SEVERE STORMS IN THE VICINITY DURING THIS PERIOD AS
WELL, SO SOMETHING TO KEEP AN EYE ON.
LOOKS LIKE WE'LL GET A BRIEF BREAK IN THE ACTION TOWARDS THE
MIDDLE OF THE WEEK AS SURFACE HIGH PRESSURE RETURNS, BUT A
FAIRLY ACTIVE WEATHER PATTERN LOOKS TO RE-COMMENCE SHORTLY
THEREAFTER INTO THE END OF THE WEEK AND NEXT WEEKEND.
CARLAW
AVIATION /00Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 627 PM CDT WED APR 23 2025
THE MAIN AVIATION WEATHER MESSAGES ARE:
- SSE WINDS THIS EVENING WILL BECOME WEAK OVERNIGHT. ANY PRECIP
THIS EVENING IS EXPECTED TO STAY NORTH OF RFD.
- A COLD FRONT WILL MOVE THROUGH ON THURSDAY, LIKELY DURING THE
MORNING, RESULTING IN A SHIFT TO NORTHEASTERLY WINDS WHICH
WILL THEN PERSIST THROUGH MUCH OF THE DAY.
- THERE IS A VERY LOW CHANCE (10% OR LESS) FOR IFR CEILINGS AT
KORD/KMDW FOLLOWING THE FRONTAL PASSAGE THURSDAY MORNING.
THE ZONE OF POTENTIAL SHOWER/THUNDERSTORM DEVELOPMENT THIS
EVENING HAS BEEN STEADILY LIFTING NORTHWARD IN TIME, AND AT
THIS POINT IT IS UNLIKELY THAT ANY PRECIP ACTIVITY WOULD OCCUR
FAR ENOUGH SOUTH TO REACH RFD. THEREFORE, DRY CONDITIONS ARE
EXPECTED TO PREVAIL THROUGH THE PERIOD AT ALL TERMINALS.
VFR CONDITIONS ARE FAVORED THROUGH THE PERIOD. WINDS ARE
EXPECTED TO WEAKEN AND SHIFT TO SSE THIS EVENING, BEFORE
BECOMING WEAK OVERNIGHT. A COLD FRONT IS EXPECTED TO ROLL OFF
LAKE MICHIGAN THURSDAY MORNING, AND WHILE THE EXACT TIMING
REMAINS UNCERTAIN WE CONTINUED TO FAVOR THE MODEL GUIDANCE THAT
IS FASTER WITH THIS FRONT, BRINGING IT THROUGH THE TERMINALS
BETWEEN 14-16Z WHICH IS LARGELY CONSISTENT WITH PREVIOUS
FORECASTS. NE WINDS AROUND 10 KNOTS SHOULD PREVAIL THROUGH MUCH
OF THE DAY BEHIND THIS FRONT. A FEW MODELS HINT AT IFR CEILINGS
AT ORD/MDW FOLLOWING THIS FRONTAL PASSAGE, BUT THESE MODELS HAVE
A POOR HANDLE OVER THE CURRENT VISBY/CEILING CONDITIONS OVER
THE LAKE. THE LAMP PROBABILITIES OF IFR CEILINGS ARE LESS THAN
10%, AND DID NOT INCLUDE ANY INDICATIONS OF THESE LOWER CLOUDS
IN THE LATEST TAFS.
NWS LINCOLN
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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