257
FXUS63 KILX 182144
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
ISSUED BY NATIONAL WEATHER SERVICE CHICAGO IL
344 PM CST MON NOV 18 2024
KEY MESSAGES
- STRONG WINDS WILL DEVELOP THIS EVENING AND CONTINUE THROUGH
TUESDAY MORNING AS A POWERFUL STORM SYSTEM LIFTS NORTHEASTWARD
THROUGH THE PLAINS. SOUTHEASTERLY TO SOUTHWESTERLY WIND GUSTS
ARE EXPECTED TO PEAK IN THE 40-50 MPH RANGE.
- SHARPLY COLDER CONDITIONS WILL BE IN STORE WEDNESDAY THROUGH
FRIDAY. IN FACT, PORTIONS OF CENTRAL ILLINOIS MAY SEE THE
FIRST SNOW FLURRIES OF THE UPCOMING SEASON WEDNESDAY NIGHT
INTO THURSDAY.
SHORT TERM
(TONIGHT TROUGH TUESDAY NIGHT)
ISSUED AT 344 PM CST MON NOV 18 2024
A SURFACE ANALYSIS TAKEN AT 21Z REVEALS AN OCCLUDING SURFACE
LOW CENTERED IN NORTHERN KANSAS WITH A SYNOPTIC COLD FRONT
EXTENDING TO ITS SOUTH DOWN THROUGH OKLAHOMA AND TEXAS AND A
WARM FRONT ARCING NORTHEASTWARD INTO SOUTHERN IOWA AND NORTHERN
ILLINOIS. THE EARLIER RAIN SHOWERS HAVE LARGELY CLEARED THE
FORECAST AREA TO THE NORTH AS THE WARM FRONT HAS CONTINUED TO
PROGRESS NORTHWARD. HOWEVER, ANOTHER BAND OF SHOWERS OUT AHEAD
OF THE SYSTEM'S TRUE COLD FRONT IS SLATED TO MOVE INTO THE AREA
THIS EVENING AS THE COLD FRONT SLIDES EASTWARD AND LARGE SCALE
FORCING FOR ASCENT INCREASES MARKEDLY WITH THE APPROACH OF AN
INCREASINGLY NEGATIVELY TILTED MID/UPPER-LEVEL TROUGH. THE
STEADIEST SHOWERS TONIGHT SHOULD LAST NO MORE THAN 3-4 HOURS AT
ANY GIVEN LOCATION, THOUGH SOME DRIZZLE/LIGHT SHOWERS MAY LINGER
AROUND UNTIL THE COLD FRONT HAS MADE ITS WAY THROUGH LATER ON
IN THE NIGHT/EARLY TOMORROW MORNING. THE AMOUNT OF LIGHTNING
STRIKES OBSERVED UPSTREAM THUS FAR HAS BEEN PRETTY PALTRY, AND
WHILE MID-LEVEL LAPSE RATES ACROSS CENTRAL ILLINOIS SHOULD
STEEPEN TO A GREATER DEGREE TONIGHT THAN WHAT THEY CURRENTLY
ARE FARTHER TO THE SOUTHWEST, THE OVERALL MEAGER AMOUNT OF
INSTABILITY LIKELY WON'T SUPPORT ANYTHING MORE THAN ISOLATED
EMBEDDED THUNDERSTORMS.
IN ADDITION TO THE RAIN, STOUT PRESSURE FALLS IN THE VICINITY
OF THE OCCLUDING LOW WILL INDUCE A PERIOD OF STRONG SOUTHEASTERLY
TO SOUTHWESTERLY WINDS TONIGHT. THERE ARE STILL SOME QUESTIONS
REGARDING THE EXTENT TO WHICH THE RAIN WILL DAMPEN MIXING INTO A
50+ KT LOW-LEVEL JET. IF THE RAIN REMAINS FAIRLY STEADY, THEN
IT'S POSSIBLE THAT MOST OF ANY 45+ MPH WIND GUSTS WILL REMAIN
CONFINED TO JUST THE MORE ROBUST CONVECTION, WHICH SHOULD HELP
PROVIDE ENOUGH OF A BOOST TO DOWNWARD MOMENTUM TRANSFER FOR WIND
ADVISORY THRESHOLDS TO BE BREACHED. HOWEVER, EVEN IF THIS WERE
TO OCCUR, A PERIOD OF AT LEAST NEAR-ADVISORY WIND GUSTS STILL
APPEARS PROBABLE TONIGHT AS LOW-LEVEL LAPSE RATES STEEPEN IN
THE COLD AIR ADVECTION REGIME BEHIND THE MAIN PUSH OF SHOWERS
(ESPECIALLY ACROSS NORTHWESTERN PORTIONS OF THE FORECAST AREA,
WHICH WILL BE IN CLOSER PROXIMITY TO THE CENTER OF THE SURFACE
LOW AND ASSOCIATED GREATER PRESSURE FALLS), SO HAVE MAINTAINED
THE INHERITED WIND ADVISORY. DID TRIM THE END TIME OF THE
ADVISORY BACK TO 12Z, THOUGH, WITH PRETTY MUCH ALL OF THE LATEST
HI-RES GUIDANCE SUGGESTING THAT GUSTS SHOULD BE WELL UNDER 45
MPH BY THAT TIME.
OTHERWISE, SKIES SHOULD START TO CLEAR OUT TOMORROW MORNING AS
A DRIER AIR MASS FILTERS INTO THE REGION. HIGH TEMPERATURES
TOMORROW SHOULD END UP RANGING FROM THE UPPER 50S TO THE MID
60S, COOLEST FARTHER NORTHWEST AND WARMEST FARTHER SOUTHEAST.
OGOREK
LONG TERM
(WEDNESDAY THROUGH MONDAY)
ISSUED AT 344 PM CST MON NOV 18 2024
A COMPLEX WEATHER PATTERN WILL EVOLVE ACROSS THE MIDWEST INTO
THE GREAT LAKES REGIONS MID TO LATE THIS WEEK AS A PHASING
OCCURS BETWEEN THE UPPER TROUGH SHIFTING EASTWARD ACROSS THE
NORTHERN ROCKIES TONIGHT AND THE WAVE CURRENTLY LIFTING
NORTHEASTWARD TOWARDS THE MID-MISSOURI VALLEY. ULTIMATELY, THIS
PROCESS IS EXPECTED TO SUPPORT A LARGE DEEPENING COLD CORE
SYSTEM RIGHT ACROSS THE LOWER GREAT LAKES REGION WEDNESDAY NIGHT
INTO THURSDAY. WHILE MUCH OF THE PRECIPITATION ASSOCIATED WITH
THIS SYSTEM LOOKS TO LARGELY REMAIN NORTH-NORTHEAST OF MUCH OF
OUR AREA WEDNESDAY AND THURSDAY, BLUSTERY NORTHWESTERLY WINDS
ALONG THE SOUTHWEST FLANK OF THIS SYSTEM WILL DRAG IN MUCH
COLDER AIRMASS INTO THE REGION. IN FACT, HIGH TEMPERATURES BY
THURSDAY COULD STRUGGLE TO REACH THE LOWER 40S IN SOME AREAS.
EXPECT THIS COLD AIRMASS TO PERSIST INTO THE FIRST PORTION OF
THE WEEKEND, BEFORE TEMPERATURES BEGIN TO MODERATE SOME SUNDAY
INTO MONDAY OF NEXT WEEK.
WHILE THE HIGHEST PRECIPITATION CHANCES WITH THIS SYSTEM
CURRENT RESIDE NORTH AND NORTHEAST OF OUR AREA, OUR OFFICIAL
FORECAST CONTINUES TO CARRY SOME LOW PROBABILITIES (GENERALLY
20-40%), ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THE MAIN
FEATURE WE ARE WATCHING FOR ANY POTENTIAL RAIN (OR EVEN RAIN
SNOW MIX) DURING THIS PERIOD IS A NOTEWORTHY MID-LEVEL IMPULSE,
WHICH MODEL AND ENSEMBLE GUIDANCE SUGGEST WILL ROUND THE BASE OF
THE DEEPENING TROUGH OVER THE OHIO VALLEY LATE WEDNESDAY, THEN
GET SLINGSHOT WEST- SOUTHWESTWARD ALONG THE NORTH/NORTHWESTERLY
PERIPHERY OF THE DEEPENING LARGER MID/UPPER-LEVEL. WHILE A GOOD
DEAL OF UNCERTAINTY EXISTS WITH HOW AND WHERE EXACTLY THIS
IMPULSE WILL TRACK, IT COULD GET IN CLOSE ENOUGH PROXIMATELY TO
OUR AREA TO SUPPORT OF A PERIOD OF RAIN AND/OR SNOW LATE
WEDNESDAY NIGHT OR THURSDAY. EITHER WAY, IT APPEARS UNLIKELY
THAT MUCH (IF ANY) SNOW ACCUMULATION WOULD MATERIALIZE INTO OUR
AREA WITH THIS IMPULSE ON THURSDAY.
PRIMARILY DRY WEATHER IS ANTICIPATED FROM FRIDAY THROUGH THE
UPCOMING WEEKEND BEFORE SOME LOW CHANCES (~20%) OF RAIN RETURN
TO THE FORECAST EARLY NEXT WEEK.
KJB
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1218 PM CST MON NOV 18 2024
LOW CLOUDS AND SHOWERS CONTINUE TO SPREAD NORTHWARD ACROSS
CENTRAL ILLINOIS EARLY THIS AFTERNOON. HOWEVER, MOST OF THE RAIN
AND LOW CIGS ARE SHOWING SIGNS OF SHIFTING NORTH OF SOME OF THE
SOUTHERN TERMINALS AT THIS TIME. THE EXPECTATION IS THAT CIGS
WILL CONTINUE TO UNDERGO IMPROVEMENT BY (IF NOT PRIOR) TO 20Z
THIS AFTERNOON AS THE SURFACE WARM FRONTAL PRECIPITATION
CONTINUES ITS NORTHWARD MIGRATION INTO NORTHERN IL EARLY THIS
AFTERNOON. OUR NEXT PERIOD OF RAIN IS THEN EXPECTED TO SHIFT
EASTWARD ACROSS THE AREA MID TO LATE THIS EVENING THROUGH THE
EARLY OVERNIGHT HOURS IN ADVANCE OF AN APPROACHING COLD FRONT. A
LOW (5-15% CHANCE) OF A RUMBLE OF THUNDER ALSO EXISTS WITH
THESE SHOWERS TONIGHT. HOWEVER, GIVEN THE LOW POTENTIAL, THERE
IS NOT FORMAL MENTION FOR TS IN THE TAFS.
WINDS WILL BECOME INCREASINGLY GUSTY (30+ KT) FROM THE
SOUTHEAST THIS EVENING AND TONIGHT AS A STRONG SURFACE LOW
TRACKS NORTHEASTWARD ACROSS THE MID-MISSOURI VALLEY. WINDS WILL
THEN SHIFT SOUTH-SOUTHWESTERLY AFTER 09Z TONIGHT AS A SURFACE
COLD FRONT SWEEPS EASTWARD ACROSS THE AREA. A PERIOD OF STRONG
WIND GUSTS (35+KT) IS POSSIBLE (40-50% CHANCE) WITH THE PASSAGE
OF THIS FRONT. THESE STRONG GUSTY WINDS WILL GRADUALLY EASE
THROUGH THE AFTERNOON AS THEY TURN WEST- SOUTHWESTERLY.
ILX WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY UNTIL 6 AM CST TUESDAY FOR ILZ027>031-036>038-
040>057-061.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page