084
FXUS63 KLOT 231022
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
522 AM CDT WED APR 23 2025
KEY MESSAGES
- SCATTERED SHOWERS/STORMS TO LIFT NEAR AND NORTH OF INTERSTATE
80 THIS MORNING. RAINFALL TOTALS WILL GENERALLY RANGE BETWEEN
A TENTH AND ONE-HALF INCH.
- THE STRETCH OF WARM WEATHER WILL CONTINUE, PAUSING BRIEFLY ON
SATURDAY BEFORE TEMPERATURES TURN EVEN WARMER EARLY NEXT WEEK.
- AN ACTIVE SPRING STORM TRACK WILL TAKE AIM AT THE LOWER GREAT
LAKES NEXT WEEK, BRINGING THE PROSPECT FOR SEVERE WEATHER.
DISCUSSION
ISSUED AT 403 AM CDT WED APR 23 2025
NEAR TERM
(THROUGH THIS AFTERNOON)
A CLUSTER OF ELEVATED THUNDERSTORMS CONTINUES TO LIFT NORTH OF
THE I-80 CORRIDOR EARLY THIS MORNING IN TANDEM WITH THE NOSE OF
A MODEST 850-MB JET. A QUICK GLANCE AT THE IR SATELLITE REVEALS
WARMING CLOUD TOPS AS THIS CONVECTIVE ACTIVITY BEGINS TO
OUTPACE THE MEAGER INSTABILITY, AND THIS TREND WILL CONTINUE AS
THE CLUSTER LIFTS FURTHER NORTH THROUGHOUT THE MORNING. STILL,
WE COULD SEE SOME PRETTY EFFICIENT RAIN RATES, WITH NEARBY
RADARS DEPICTING INSTANTANEOUS RATES OF 0.5-1"/HR. THIS LINES UP
REASONABLY WELL WITH RECENT HREF 3-HR PMM QPF GUIDANCE, WHICH
OFFERS 0.1"-0.5" WITH THIS ACTIVITY. ONE BYPRODUCT OF THESE
EARLY MORNING STORMS IS ITS ASSOCIATED CONVECTIVE DEBRIS/OUTFLOW
WHICH RESULT IN A BUSTED TEMPERATURE FORECAST THIS AFTERNOON. A
FEW OF THE HI-RES GUIDANCE, NAMELY THE HRRR, CONTINUE TO HINT
AT THIS POSSIBILITY, EVEN OFFERING ADDITIONAL SHOWERY ACTIVITY
THIS AFTERNOON NORTH OF I-88 AS SUBTLE MID-LEVEL SHORTWAVE
ENERGY INTERACTS WITH A LINGERING SFC BOUNDARY. AREAS SOUTH OF
I-80 SHOULD EASILY REACH THE UPPER 70S THIS AFTERNOON, WHILE
AREAS NORTH OF I-88 MAY STRUGGLE TO BREACH THE UPPER 60S.
SHORT TERM
(TONIGHT THROUGH SATURDAY)
A POCKET OF MID-LEVEL DRY AIR WILL MOVE ACROSS THE AREA TONIGHT
THROUGH THURSDAY, KEEPING RAIN CHANCES AT BAY. CONTINUED WARM
ADVECTION WILL PUSH TEMPERATURES NEAR 80S DEGREES IN AREAS SOUTH
OF I-80 THURSDAY AFTERNOON. THE JOKE WILL ONCE AGAIN BE ON AREAS
NORTH OF I-88, BUT PARTICULARLY ALONG THE LAKEFRONT, AS A
BACKDOOR FRONT SAGS INTO THE LOWER GREAT LAKES REGION. THE NET
EFFECT WILL BE SHARP TEMPERATURE GRADIENT ACROSS OUR CWA, WITH
LOWER 70S NORTH OF I-88 AND LOWER 60S SMACK-UP AGAINST THE
LAKESHORE. AND, A SIMILAR TREND CONTINUES FRIDAY AS THE EAST-
WEST FRONT STALLS IN THE VICINITY OF I-80.
RAIN CHANCES RE-EMERGE FRIDAY MORNING OR FRIDAY AFTERNOON AS
MID-LEVEL SHORTWAVE ENERGY AND WEAK SFC LOW PRESSURE GLIDES
ALONG THE NEAR-STATIONARY FRONT. OVERALL, THE VERTICAL MOISTURE
PROFILE WITH THIS ACTIVITY LOOKS FAIRLY PALTRY WITH SOME
RESIDUAL MID-LEVEL DRY AIR IN PLACE. WHILE THIS SETUP DOESN'T
APPEAR TO DELIVER A GOOD SOAKER, THERE IS AN AXIS OF MODEST
MLCAPE (500-1000 J/KG) NEAR AND SOUTH OF THE FRONT WHERE
CONVECTIVE PRECIP MAY OVERACHIEVE OUR CURRENT QPF EXPECTATIONS.
MUCH COOLER TEMPERATURES WILL SPILL ACROSS THE REGION FRIDAY
NIGHT INTO SATURDAY AS A ROBUST MID-LEVEL TROUGH DIGS ACROSS THE
UPPER-MISSISSIPPI VALLEY AND HELPS FLUSH OUR LINGERING FRONT
WELL TO THE SOUTH. TEMPERATURES SATURDAY AFTERNOON WILL ONLY
WARM INTO THE LOWER 60S INLAND, AND LOWER 50S ALONG THE
LAKEFRONT.
LONG TERM
(SUNDAY THROUGH TUESDAY)
AFTER A SEASONABLY CHILLY SATURDAY, TEMPERATURES BOUNCE WARMER
BY SUNDAY AS A RIDGE OF HIGH PRESSURE QUICKLY BUILDS ACROSS THE
PLAINS AHEAD OF DEEP WESTERN TROUGH. AN IMPRESSIVE WARM
ADVECTION REGIME WILL PUSH TEMPERATURES INTO THE 70S BY SUNDAY
AND INTO THE LOWER 80S MONDAY - TUESDAY. OF COURSE, WE CAN'T
SURGE INTO THE 80S THIS TIME OF YEAR WITHOUT IT BEING
ACCOMPANIED WITH GUSTY SOUTHERLY WINDS. A QUICK GLANCE AT
GEFS/EPS GUIDANCE SUPPORTS MEAN WIND GUSTS AROUND 30-40 MPH AS
THE SURFACE PRESSURE GRADIENT TIGHTENS AHEAD OF AN IMPENDING
STORM SYSTEM. AND IN THAT SAME BREATH, MULTIPLE MACHINE-LEARNING
TOOLS ARE HIGHLIGHTING THE MID- TO-UPPER MISSISSIPPI VALLEY TO
LOWER GREAT LAKES REGION FOR SEVERE WEATHER DURING THE MONDAY-
TUESDAY TIMEFRAME NEXT WEEK.
NWS LINCOLN
AVIATION /06Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 1226 AM CDT WED APR 23 2025
KEY AVIATION MESSAGES:
- SCATTERED SHOWERS REMAIN A POSSIBILITY (40% CHANCE) THROUGH
ABOUT 15Z/10AM THIS MORNING.
- GENERALLY LIGHT SURFACE WINDS (5-12 KTS) WILL OSCILLATE
BETWEEN SOUTHWEST AND EAST THROUGH THIS EVENING.
WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS EASTERN
IOWA EARLY THIS MORNING, COINCIDING WITH A WEAK SURFACE FRONT.
THIS ACTIVITY WILL ATTEMPT TO MOVE EASTWARD INTO NORTH CENTRAL
AND NORTHEAST ILLINOIS TOWARD SUNRISE. WHILE SCATTERED SHOWERS
REMAIN PLAUSIBLE, AND HAVE THEREFORE BEEN MAINTAINED FOR THE
REGIONAL TERMINALS, SOME QUESTION AS TO WHETHER THUNDER CHANCES
MAY PERSIST. FOR NOW, CONFIDENCE AND COVERAGE REMAIN LOW ENOUGH
TO NOT MENTION THUNDER IN THIS ROUND OF TAFS; THINKING THAT THE
CURRENT STORMS WILL OUTPACE THE MEAGER INSTABILITY. WE WILL
CONTINUE TO MONITOR TRENDS AND ADJUST ACCORDINGLY.
OTHERWISE, THE OTHER CHALLENGE TODAY WILL BE SURFACE WINDS.
WHILE BLENDED FORECAST GUIDANCE SUGGESTS A SOUTHWESTERLY WIND
THROUGH MUCH OF THE DAY, WE WILL NEED TO KEEP WATCH OF HOW THE
IMPENDING SHOWERS THIS MORNING MIGHT DISRUPT THE AMBIENT FLOW BY
AFTERNOON. COULD WELL BE DEALING WITH THE DREADED VARIABLE WIND.
NWS CHICAGO
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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