337
FXUS63 KIND 181702
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1202 PM EST MON NOV 18 2024
KEY MESSAGES
- SPRINKLES AND LIGHT RAIN TODAY
- MORE WIDESPREAD RAIN TONIGHT INTO TUESDAY
- MUCH COLDER WEATHER WEDNESDAY NIGHT THROUGH SATURDAY WITH THE
POTENTIAL FOR THE FIRST SNOWFLAKES OF THE YEAR WEDNESDAY NIGHT INTO
THURSDAY
- BREEZY WEDNESDAY AND THURSDAY AFTERNOON WITH GUSTS OF 25-35 MPH
FORECAST UPDATE
ISSUED AT 916 AM EST MON NOV 18 2024
COVERAGE OF LIGHT PRECIPITATION IS GRADUALLY INCREASING ACROSS THE
WESTERN COUNTIES AS THE PRECIPITATION SHIELD GRADUALLY MOVES
NORTHWARD. THERE IS A FAIRLY TIGHT GRADIENT IN THE ISENTROPIC LEFT
THAT TAPERS DOWN EAST OF THE WABASH RIVER WITH THE STRONGER LLJ
FURTHER WEST INTO MISSOURI AND ILLINOIS. THUS CONFIDENCE IN
PRECIPITATION MUCH MORE THAN A FEW SPRINKLES TOWARDS INDIANAPOLIS IS
LOW UNTIL LATER INTO THE AFTERNOON HOURS WHEN THE LLJ GETS A MORE
SOUTHWESTERLY ORIENTATION AND ALLOWS FOR BETTER ISENTROPIC LIFT INTO
CENTRAL INDIANA. AFTERNOON HIGHS IN THE MID 60S STILL LOOK TO BE ON
TRACK WITH A MILD START TO THE DAY ONGOING.
A BREAK IN PRECIPITATION IS THEN LIKELY FOR THE EVENING TO EARLY
OVERNIGHT HOURS BEFORE THE STRONGER FORCING ASSOCIATED WITH THE MAIN
LOW PRESSURE SYSTEM MOVES IN AFTER 06Z TONIGHT.
SHORT TERM (TODAY AND TONIGHT)
ISSUED AT 312 AM EST MON NOV 18 2024
SUBTROPICAL MOISTURE PLUME IS PRESENT ACROSS THE AREA AND BROAD/WEAK
ISENTROPIC ASCENT IS RESULTING IN SOME SPRINKLES OR LIGHT RAIN
ACROSS PORTIONS OF THE AREA THIS MORNING. THIS COULD INCREASE SOME
WITHIN A WEST-NORTHWEST TO EAST-SOUTHEAST ORIENTED BAND LATER THIS
MORNING THROUGH THE AFTERNOON AS STRONGER CONVERGENCE AT THE LEADING
EDGE OF LOW LEVEL JET CAUSES INCREASING ASCENT. AMOUNTS SHOULD BE
LIGHT, GENERALLY A FEW HUNDREDTHS OF AN INCH FOR AREAS THAT DO
RECEIVE RAIN.
WARM ADVECTION IS STRONG ENOUGH FOR TEMPERATURES TO BE NEARLY 15
DEGREES ABOVE MID-NOVEMBER CLIMATOLOGY (MID TO UPPER 60S). IT
APPEARS PRECIPITATION WILL BE LIMITED IN COVERAGE AND INTENSITY
ENOUGH NOT TO INTERFERE WITH THIS SIGNIFICANTLY, ESPECIALLY ACROSS
SOUTHERN PORTIONS OF THE AREA WHERE PRECIPITATION WILL EXIT EARLIER.
LARGE SCALE ASCENT FROM THE PLAINS LOW PASSING TO OUR NORTHWEST AND
ANOMALOUS MOISTURE WITHIN ITS WARM CONVEYOR BELT WILL BRING A BAND
OF SHOWERS TONIGHT. HREF PROBABILITY MATCH-MEAN PRECIPITATION
AMOUNTS OF 0.10-0.25 INCHES ALIGNS WITH MULTI-MODEL MEAN. THE MAIN
OUTLIER IS THE DETERMINISTIC ECMWF, EVEN AMONG ITS EPS MEMBERS.
THERE IS SOME CONCERN THAT WHEN COMPARED TO PREVIOUS RAIN EVENTS,
THIS ONE DISPLAYS A STRONGER WARM NOSE AND A SLIVER OF CAPE ABOVE
THAT WHICH COULD SUPPORT CONVECTIVE ELEMENTS AND SOME ENHANCEMENT TO
THE AFOREMENTIONED AMOUNTS. THIS TENDS TO GET WASHED OUT IN THE MEAN
AND SHOULD BE LOCALIZED, BUT >0.50" AMOUNTS ARE POSSIBLE AT A FEW
LOCATIONS.
STRENGTHENING MSLP GRADIENT WILL CAUSE SOUTHEASTERLY WINDS TO
STEADILY INCREASE THROUGHOUT THE DAY, PEAKING TONIGHT.
LONG TERM (TUESDAY THROUGH SUNDAY)
ISSUED AT 312 AM EST MON NOV 18 2024
THE LONG ADVERTISED DRAMATIC COOLDOWN FOR MID TO LATE WEEK CONTINUES
TO BE THE PRIMARY FOCUS OF THE LONG TERM PERIOD, ALONG WITH
POTENTIAL FOR THE FIRST SNOWFLAKES OF THE SEASON ASSOCIATED BOTH
WITH A LARGE UPPER LOW EXPECTED TO PUSH ACROSS THE GREAT LAKES AND
OHIO VALLEY REGION DURING THE PERIOD AND POSSIBLE LAKE ENHANCEMENT
AS EARLY SEASON LAKE TEMPERATURES ARE RUNNING WELL ABOVE NORMAL.
THE PRIMARY COLD FRONT WILL PUSH ACROSS THE AREA ON TUESDAY. THIS
WILL BRING RAINFALL TO AN END ACROSS THE AREA BY MID TO LATE
AFTERNOON TUESDAY AT THE LATEST, WITH A BREAK TUESDAY NIGHT AS A
REINFORCING SHOT OF COLDER AIR FOLLOWS IN THE WAKE OF THE INITIAL
FRONT.
WHILE MODELS CONTINUE TO FOCUS STRONGER SURFACE CYCLOGENESIS TO OUR
EAST WEDNESDAY INTO THURSDAY, SIGNIFICANT RUN TO RUN INCONSISTENCIES
CONTINUE TO KEEP FORECAST CONFIDENCE LOW OVERALL IN SPECIFICS.
NONETHELESS, PRECIPITATION CHANCES WILL RETURN WITH THE UPPER LOW
AND POTENTIALLY THE BACKSIDE OF ANY SURFACE CYCLONE WEDNESDAY INTO
THURSDAY/FRIDAY, WITH TEMPERATURES BECOMING COLD ENOUGH WEDNESDAY
NIGHT INTO THURSDAY TO POTENTIALLY SUPPORT THE FIRST SNOWFLAKES OF
THE SEASON. PROFILES MAY EVEN BECOME COLD ENOUGH TO SUPPORT BRIEF
PERIODS OF ALL SNOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY, THOUGH
VERY WARM GROUND OWING TO THE SIGNIFICANTLY ABOVE NORMAL
TEMPERATURES EXPERIENCED MUCH OF THE LAST SEVERAL WEEKS AND IN THE
FIRST FEW DAYS OF THIS WEEK SHOULD MITIGATE ANY REAL ACCUMULATION
CHANCE OUTSIDE OF BRIEF BURSTS OF HIGHER RATES, PERHAPS AS A RESULT
OF LAKE ENHANCEMENT.
BROADLY SPEAKING, HOWEVER, THE MESSAGE REMAINS THE SAME - THE
COLDEST CONDITIONS OF THE SEASON THUS FAR ARE EXPECTED LATE THIS
WEEK, WITH DREARY AND BREEZY CONDITIONS (FREQUENT 25-35+ MPH GUSTS),
AND FREQUENT CHANCES FOR SHOWERS, PERHAPS WITH SOME SNOWFLAKES,
DURING THE LATTER HALF OF THE WORK WEEK. MOST IF NOT ALL OF THE SNOW
APPEARS LIKELY TO MELT AS IT FALLS, BUT A LIGHT COATING DURING THE
COOLEST TIMES AND IN THE MOST INTENSE SNOW SHOWERS CANNOT BE
ENTIRELY RULED OUT.
TEMPERATURES MAY MODERATE A BIT VERY LATE IN THE PERIOD INTO EARLY
NEXT WEEK, THOUGH CONTINUED AND GROWING MODEL DIFFERENCES AT THAT
TIME FRAME MAKE THIS VERY UNCERTAIN.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 1201 PM EST MON NOV 18 2024
IMPACTS:
- MVFR CIGS THROUGH 21Z
- OCCASIONAL MVFR TO IFR VSBYS DUE TO RAIN THROUGH 21Z, AGAIN AFTER
06Z THROUGH 09Z
- LLWS 06Z TO 10Z
- SOUTHEASTERLY WIND GUSTS TO 20KTS AFTER 03Z
DISCUSSION:
MVFR CIGS WILL CONTINUE TO SLOWLY IMPROVE TO VFR THIS AFTERNOON AS
RAIN MOVES THROUGH. RAIN COVERAGE WILL BE HIGHEST AT LAF AND HUF
WITH MINIMAL RAIN AT IND AND BMG. VSBYS WILL REMAIN VFR OUTSIDE OF
THE HEAVIEST SHOWERS. ADDITIONAL RAIN WILL MOVE IN TONIGHT AFTER 06Z
ALONG WITH A STRONG LLJ WHICH WILL BRING LLWS. CIGS ARE EXPECTED TO
DROP BACK TO MVFR AFTER THE RAIN COMES TO AN END. WINDS WILL REMAIN
LIGHT THROUGH THE DAY TODAY BEFORE SOUTHEASTERLY GUSTS OF 20KTS
BEGIN AFTER 03Z WITH THE STRONGEST WINDS LIKELY BETWEEN 09Z AND 14Z.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...WHITE
SHORT TERM...BRB
LONG TERM...NIELD
AVIATION...WHITE
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