644
FXUS63 KIND 151957
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
257 PM EST SUN DEC 15 2024
KEY MESSAGES
- WIDESPREAD RAIN EXPECTED LATE TONIGHT INTO MONDAY WITH A LOW
CHANCE FOR EMBEDDED THUNDERSTORMS.
- WIND GUSTS BETWEEN 25-35 MPH POSSIBLE DURING THE DAY MONDAY.
- CHANCE OF RAIN TUESDAY NIGHT INTO WEDNESDAY, SOME SNOW MAY MIX IN
FURTHER NORTH
- COOLING TREND WEDNESDAY ONWARD
SHORT TERM (THIS EVENING THROUGH MONDAY)
ISSUED AT 257 PM EST SUN DEC 15 2024
THROUGH THIS EVENING...
MOSTLY QUIET WEATHER CONDITIONS ARE EXPECTED THROUGH THIS EVENING AS
UPPER RIDGING BRIEFLY BUILDS IN BEHIND A DEPARTING UPPER LOW.
CURRENT SATELLITE IMAGERY SHOWS EXTENSIVE CLOUD COVER ACROSS THE
REGION WITH SOME BREAKS IN THE CLOUDS ACROSS SOUTH-CENTRAL IN. THIS
IS DUE TO DRY AIR ADVECTION WHICH SHOULD CONTINUE HELPING TO BREAK
UP THE CLOUDS. CLOUDS HAVE KEPT MOST AREAS NORTH OF THE I-70
CORRIDOR IN THE 40S. MEANWHILE, TEMPERATURES HAVE WARMED WELL INTO
THE 50S FURTHER SOUTHWEST. THERE IS A VERY LOW CHANCE FOR PATCHY
DRIZZLE ACROSS NORTHEASTERN PORTIONS OF THE AREA WHERE DEEPER LOW-
LEVEL MOISTURE IS STILL PRESENT.
TONIGHT...
EXPECT CLOUDS TO QUICKLY INCREASE ONCE AGAIN AS DEEPER MOISTURE
SURGES NORTHWARD AHEAD OF AN APPROACHING SURFACE LOW AND PARENT
TROUGH. DRY CONDITIONS ARE EXPECTED EARLY IN THE OVERNIGHT PERIOD
THOUGH FORECAST SOUNDINGS SHOW INCREASING LOW-LEVEL MOISTURE BENEATH
A SUBSIDENCE INVERSION SUGGESTING PATCHY DRIZZLE IS POSSIBLE AT
TIMES. BY LATE TONIGHT, INCREASING LOW-LEVEL THETA-E ADVECTION AHEAD
OF A COLD FRONT WILL LEAD TO HEAVIER AND MORE WIDESPREAD
PRECIPITATION. SHOWERS MAY CONTAIN EMBEDDED CONVECTIVE ELEMENTS WITH
THE POTENTIAL FOR A FEW RUMBLES OF THUNDER. LOOK FOR STRENGTHENING
SOUTHERLY FLOW TO SUPPORT INCREASING TEMPERATURES.
MONDAY...
EXPECT WIDESPREAD RAIN TO CONTINUE INTO MONDAY AS THE AFOREMENTIONED
SYSTEM PROGRESSES THROUGH THE REGION. THE STRONGEST FORCING AND
DEEPER MOISTURE AHEAD OF THE COLD FRONT SHOULD ALIGN OVER FAR
SOUTHERN PORTIONS OF CENTRAL INDIANA RESULTING IN GREATER QPF
AMOUNTS. MOST GUIDANCE SHOWS AN AXIS OF 1-2" OF RAIN NEAR THIS AREA,
BUT SOME MODELS SUGGEST THE HEAVIER RAINFALL COULD BE JUST SOUTH OF
THE CWA.
THE COLD FRONT WILL DEPART DURING THE AFTERNOON WITH PRECIPITATION
DIMINISHING FROM WEST TO EAST. LOOK FOR CLOUDS TO ALSO DECREASE
DURING THE AFTERNOON. HOWEVER, INCREASING SUBSIDENCE ABOVE LINGERING
LOW-LEVEL MOISTURE SHOULD LEAD TO THE DEVELOPMENT OF A LOW CLOUD
DECK TOWARDS THE EVENING HOURS. GUSTY WINDS AROUND 25-35 MPH ARE
POSSIBLE DURING THE DAY THANKS TO A STRONG PRESSURE GRADIENT AND
LLJ. EXPECT AN ABNORMALLY WARM WINTER DAY WITH HIGHS RANGING FROM
THE MID 50S TO LOW 60S.
LONG TERM (MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 257 PM EST SUN DEC 15 2024
A RETURN TO COOLER CONDITIONS IS ANTICIPATED DURING THE LONG RANGE.
ALOFT, THE JET PATTERN WILL SHIFT FROM QUASIZONAL TO MORE AMPLIFIED
WITH TROUGHING DOMINANT OVER THE EASTERN SEABOARD. SUCH A PATTERN
TYPICALLY BRINGS DRY AND COOLER CONDITIONS SINCE NORTHWESTERLY FLOW
PREVAILS. THESE CONDITIONS CAN LARGELY BE EXPECTED BY THE END OF THE
LONG RANGE. HOWEVER, BEFORE WE FULLY SWITCH INTO SUCH A PATTERN
THERE IS AT LEAST ONE MORE WAVE EMBEDDED WITHIN THE ZONAL FLOW
ALOFT. THIS WAVE IS EXPECTED TO ARRIVE EARLY ON WEDNESDAY BRINGING
ANOTHER ROUND OF PRECIPITATION.
MODEL UNCERTAINTY IS ON THE HIGHER SIDE REGARDING THIS SYSTEM, MAINLY
IN TERMS OF ITS TRACK. SOME GUIDANCE BRINGS THE SYSTEM TO OUR NORTH
WHILE OTHERS BRING IT FURTHER SOUTH. THOUGH THE OVERALL THERMAL
PROFILE AHEAD OF THE SYSTEM IS QUITE WARM...THE FURTHER SOUTH
OPTIONS MAY HAVE ENOUGH COLD AIR TO WORK WITH FOR SOME MIXED PRECIP
TYPES, MAINLY ON THE BACK SIDE OF THE LOW AS IT DEPARTS. WITHIN THE
MEMBERS THAT SHOW A FURTHER NORTH OPTION...HEAVY RAINFALL MAY BE THE
PRIMARY WEATHER CONCERN AS THERE MAY BE EMBEDDED CONVECTION
ASSOCIATED WITH THE LOW-LEVEL JET AND WARM CONVEYOR. WE WILL
MAINTAIN CHANCE POPS UNTIL GUIDANCE CONVERGES AND A TREND BECOMES
CLEAR.
ONCE THE MID-WEEK SYSTEM DEPARTS, TROUGHING BEGINS TO DIG OVER THE
EASTERN SEABOARD AND OUR TRANSITION TO NORTHWESTERLY FLOW COMMENCES.
AS SUCH, TEMPERATURES TREND DOWNWARD TOWARDS COLDER MORE WINTER-LIKE
VALUES. THOUGH THE OVERALL PATTERN WILL BE DRY, GUIDANCE SHOWS A
CLIPPER SYSTEM (SOME MEMBERS DEPICTING A FAIRLY ROBUST LOW) DIVING
SOUTHEASTWARD TOWARDS THE END OF THE WEEK WITH POTENTIAL IMPACTS TO
INDIANA. MOST GUIDANCE KEEPS INDIANA LARGELY DRY AS THE BULK OF THE
PRECIPITATION ASSOCIATED WITH THE SYSTEM IS ON ITS NORTHERN FLANK.
THERE ARE A FEW MEMBERS THAT BRING SNOW SHOWERS TO THE REGION,
HOWEVER. TEMPERATURES ON FRIDAY WILL DEPEND ON HOW STRONG THE SYSTEM
IS, AND WHERE IT TRACKS. REGARDLESS, COLD CONDITIONS ARE LIKELY TO
FOLLOW WITH RENEWED COLD AIR ADVECTION BEHIND THE DEPARTING SYSTEM.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 1247 PM EST SUN DEC 15 2024
IMPACTS:
- GENERALLY MVFR CONDITIONS EXPECTED THROUGH THE AFTERNOON WITH
BRIEF PERIOD OF VFR POSSIBLE THIS EVENING
- BORDERLINE IFR/LIFR CEILINGS RETURN LATE OVERNIGHT
- PATCHY DRIZZLE LATE TONIGHT WITH WIDESPREAD SHOWERS EXPECTED
TOWARDS DAYBREAK MONDAY
- GUSTY WINDS AROUND 20-35KTS POSSIBLE DURING THE DAY MONDAY,
STRONGEST GUSTS LATE IN THE DAY
DISCUSSION:
GENERALLY MVFR CEILINGS EXPECTED THROUGH THE DAY AS AN UPPER LOW
MOVES ACROSS THE REGION. SOME VFR CONDITIONS ARE POSSIBLE LATE THIS
AFTERNOON INTO THE EVENING THOUGH THIS WILL BE BRIEF. CEILINGS FALL
ONCE AGAIN TONIGHT WITH BORDERLINE IFR/LIFR CEILINGS EXPECTED AFTER
06Z. CEILINGS WILL REMAIN LOW UNTIL A COLD FRONT PUSHES THROUGH
MIDDAY MONDAY.
AREAS OF RAIN AND DRIZZLE WILL REDUCE VISIBILITIES AT TIMES LATE
TONIGHT INTO MONDAY MORNING AS ANOTHER SYSTEM MOVES THROUGH. THERE
IS A LOW CHANCE FOR LLWS TOWARDS DAYBREAK MONDAY, BUT CONFIDENCE
IS NOT HIGH ENOUGH TO WARRANT A TAF MENTION. EXPECT GUSTY SW WINDS
AROUND 20-35 KTS DURING THE DAY MONDAY WITH HIGHEST GUSTS
EXPECTED DURING THE AFTERNOON AND EVENING.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...MELO
LONG TERM...ECKHOFF
AVIATION...MELO
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