469
FXUS63 KIND 152359
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
659 PM EST SUN DEC 15 2024
KEY MESSAGES
- PATCHY TO AREAS OF FOG THROUGH MIDNIGHT ACROSS WESTERN AND NORTH
CENTRAL INDIANA.
- 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 658 PM EST SUN DEC 15 2024
FOG HAS BEGUN TO FORM ACROSS MUCH OF WESTERN AND NORTH CENTRAL
INDIANA AS WINDS HAVE DROPPED TO NEAR CALM AND CLOUDS REMAIN
SCATTERED TO BROKEN ACROSS THE AREA. THIS COMBINED WITH RECENT
RAINFALL HAS ALLOWED FOR AREAS OF FOG, LOCALLY DENSE TO BECOME OVER
THE LAST HOUR. WIND SPEEDS ARE EXPECTED TO GRADUALLY INCREASE ALONG
WITH AN INCREASE IN CLOUD COVER TOWARDS 9PM WHICH SHOULD ALLOW FOR A
GRADUAL DISSIPATION OF THE MORE WIDESPREAD FOG LATER INTO THE
EVENING AND EARLY OVERNIGHT, BUT LOCALIZED RIVER VALLEY MAY SEE FOG
CONTINUE THROUGH MUCH OF THE NIGHT.
HAVE ADJUSTED THE FORECAST WITH A FOCUS ON AREAS NORTH OF I-70 AND
HIGHEST COVERAGE FROM TERRE HAUTE TO KOKOMO. WILL BE COORDINATING
WITH NEIGHBORING OFFICES TO DISCUSS IF THERE'S A NEED FOR A DENSE
FOG ADVISORY BUT AT THIS TIME THE COVERAGE AND DURATION OF DENSE FOG
LOOKS TO BE LOW ENOUGH THAT A HEADLINE ISN'T NEEDED AT THIS TIME.
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 (00Z TAF ISSUANCE/UPDATE)
ISSUED AT 658 PM EST SUN DEC 15 2024
IMPACTS:
-MVFR CIGS TO BECOME IFR AND BRIEFLY LIFR AFTER 06Z
-MVFR TO BRIEFLY IFR CIGS DUE TO RAIN 09Z TO 16Z
-WESTERLY WIND GUSTS TO 25KTS AFTER 16Z
-TRANSIENT FG AT HUF AND LAF THROUGH 08Z.
DISCUSSION:
MADE AN ADJUSTMENT TO HUF AND LAF TO ACCOUNT FOR PERIODS OF FOG THAT
MAY OCCASIONALLY DROP VSBYS TO 1/4SM THROUGH 08Z.
LOW VFR TO HIGH MVFR CIGS WILL GRADUALLY DETERIORATE TO LOW
MVFR/HIGH IFR CIGS AFTER 06Z AHEAD OF LIGHT RAIN AFTER 10Z. THERE
MAY BE BRIEF PERIODS OF DRIZZLE WITH LIFR CONDITIONS BETWEEN 08Z AND
11Z, BUT CONFIDENCE IS LOW. STEADIER RAIN ARRIVES AFTER 12Z WITH
BRIEF HEAVIER SHOWERS BRINGING MVFR TO IFR VSBYS THROUGH 16Z. CLOUDS
WILL THEN GRADUALLY CLEAR THROUGH THE AFTERNOON WITH WESTERLY WIND
GUSTS TO 25KTS ALONG WITH A LOW CHANCE FOR GREATER THAN 30KTS AT
LAF/HUF.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...WHITE
SHORT TERM...MELO
LONG TERM...ECKHOFF
AVIATION...WHITE
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