845
FXUS63 KIND 160604
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
104 AM EST MON DEC 16 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.
FORECAST UPDATE
ISSUED AT 104 AM EST MON DEC 16 2024
SURFACE OBSERVATIONS AND WEBCAMS SHOW THAT THE DENSE FOG HAS ENDED
ACROSS CENTRAL INDIANA EARLY THIS MORNING. THUS HAVE LET THE DENSE
FOG ADVISORY EXPIRE. PATCHY FOG WILL PERSIST THROUGH THE NIGHT
THOUGH.
ADJUSTED TEMPERATURES SOME AS WELL AS WARMER AIR CONTINUES TO WORK
NORTH, BUT SOME COOLER AIR PERSISTS ACROSS THE FAR NORTHWEST
PORTIONS OF THE AREA.
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 (06Z TAF ISSUANCE)
ISSUED AT 1236 AM EST MON DEC 16 2024
IMPACTS:
-IFR AND POTENTIALLY LOWER CEILINGS FOR MUCH OF THE FIRST 12 HOURS
-RAIN RETURNS BY 12Z AND CONTINUES INTO EARLY AFTERNOON
-WESTERLY WIND GUSTS TO 25KTS AFTER 16Z
-IMPROVEMENT TO VFR BY 170000Z
DISCUSSION:
DENSE FOG HAS LIFTED NORTH OF THE SITES, WITH ALL BUT KLAF SEEING
6SM OR GREATER. IFR CEILINGS WILL CONTINUE TO SPREAD NORTH AND REACH
KLAF EARLY.
IFR CEILINGS WILL CONTINUE THROUGH 18Z OR SO THEN GRADUAL
IMPROVEMENT WILL OCCUR. LOWER THAN IFR CEILINGS ARE POSSIBLE AT
TIMES.
EMBEDDED ISOLATED CONVECTION IS POSSIBLE IN THE RAIN, BUT ODDS ARE
TOO LOW TO MENTION.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...50
SHORT TERM...MELO
LONG TERM...ECKHOFF
AVIATION...50
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