061
FXUS63 KIND 170702
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
202 AM EST SUN NOV 17 2024
KEY MESSAGES
- WARMING TREND BACK TO THE 60S BEGINS SUNDAY
- WARMER THAN AVERAGE WEATHER CONTINUES THROUGH TUESDAY
- WINDY AND MUCH COOLER AFTER WEDNESDAY WITH GUSTS TO 40 MPH THURSDAY
- POTENTIAL FOR THE FIRST SNOW OF THE YEAR WEDNESDAY NIGHT INTO
THURSDAY
FORECAST UPDATE
ISSUED AT 846 PM EST SAT NOV 16 2024
GOES-16 NIGHTTIME MICROPHYSICS LOOP AND OBS WERE INDICATING PLENTY
OF CLEARING ACROSS CENTRAL INDIANA THIS EVENING. HOWEVER, 305K
ISENTROPIC LIFT AND SOUTHWEST FLOW IN THE WAKE OF AN UPPER OHIO
VALLEY UPPER RIDGE AND IN ADVANCE OF NORTHERN PLAINS AND SOUTHWEST
TROUGHING WILL BRING IN SOME MID AND HIGH CLOUDS OVERNIGHT. HI-RES
SOUNDINGS ARE REVEALING MUCH LESS MOISTURE TRAPPED UNDER A VERY
STRONG INVERSION. THIS AND BUFKIT SUGGEST LOW LEVEL STRATUS AND OR
FOG WILL LIKELY NOT BE A BID ISSUE TONIGHT. MEANWHILE, SOUTHEAST
WINDS 5 TO 10 KNOTS IN THE WAKE OF THE SURFACE RIDGE SHOULD KEEP
TEMPERATURES FROM FALLING MUCH OVERNIGHT WITH LOWS MOSTLY IN THE
LOWER TO MIDDLE 40S EXPECTED.
SHORT TERM (THIS EVENING THROUGH SUNDAY)
ISSUED AT 148 PM EST SAT NOV 16 2024
DESPITE THE UPPER RIDGE AXIS OVERHEAD AND A STOUT BOUNDARY LAYER
INVERSION NOTED NICELY ON THE KIND ACARS...A PERSISTENT SOUTHEAST
FLOW HAS ENABLE MODEST MIXING WITHIN THE LOWER LEVELS ACROSS THE
SOUTHWEST HALF OF THE FORECAST AREA SO FAR THIS AFTERNOON. THE
RESULT HAS BEEN A SCATTERING OF THE STRATUS ESSENTIALLY ALONG AND
WEST OF I-65. 19Z TEMPERATURES HAD RISEN INTO THE 50S ACROSS CENTRAL
INDIANA.
THE QUESTION FOR TODAY WAS ALWAYS HOW MUCH WE COULD SCATTER THE
LOWER CLOUDS AND WHILE INITIALLY PESSIMISTIC THIS MORNING BASED ON
THE ITEMS MENTIONED ABOVE...WE ARE MIXING BETTER THAN PREVIOUSLY
EXPECTED. THIS WILL AT LEAST PROVIDE BETTER OPPORTUNITIES AT
SUNSHINE THROUGH THE REST OF THE AFTERNOON FOCUSED ESPECIALLY ACROSS
THE SOUTHWEST HALF OF THE FORECAST AREA. THAT BEING SAID...THE
PRESENCE OF THE INVERSION INTO THIS EVENING WILL KEEP STRATUS FROM
FULLY MIXING OUT THROUGH SUNSET.
THE REST OF THE NEAR TERM THROUGH SUNDAY WILL BE QUIET AS THE OHIO
VALLEY REMAINS UNDER THE INFLUENCE OF THE SURFACE RIDGE CURRENTLY
SHIFTING EAST OF THE AREA. THIS FEATURE WILL DROP SOUTH INTO SUNDAY
AND REFOCUS ACROSS THE SOUTHERN APPALACHIANS...STILL IN CLOSE ENOUGH
PROXIMITY TO MAINTAIN A SOLID INFLUENCE ACROSS THE REGION.
HOW MUCH THE LOWER DECK ERODES ACROSS THE REGION BY THIS EVENING
WILL BE A FACTOR IN THE AMOUNT OF ANY REEXPANSION AS THE BOUNDARY
LAYER INVERSION LINGERS. PRIMARY FOCUS FOR STRATUS REDEVELOPMENT
WILL BE ACROSS NORTHERN COUNTIES WHERE THE DEEPEST MOISTURE WILL
REMAIN THROUGH EARLY SUNDAY. FURTHER SOUTH ACROSS THE FORECAST
AREA DRIER AIR WILL FILTER DOWN INTO THE LOWER LEVELS BUT
INCREASING HIGH LEVEL CLOUDS WILL OVERSPREAD THE REGION AHEAD OF
THE FRONTAL BOUNDARY EXTENDING FROM THE UPPER MIDWEST SOUTH INTO
TEXAS.
THE LOWER CLOUDS WILL DISSIPATE ENTIRELY ACROSS NORTHERN PORTIONS OF
THE FORECAST AREA SUNDAY MORNING...LEAVING A MIX OF SUN AND CLOUDS
WITH A GRADUAL INCREASE IN MID AND HIGH LEVEL CLOUDS THROUGHOUT THE
DAY AS THE WEAKENING BOUNDARY APPROACHES. SOUTHWEST FLOW AHEAD OF
THE FRONT WILL BE PERIODICALLY GUSTY BY SUNDAY AFTERNOON...
ESPECIALLY OVER THE WABASH VALLEY.
TEMPS...DESPITE SOME CLEARING TONIGHT...STEADY SOUTHERLY FLOW AND
WARM ADVECTION WILL KEEP LOWS PRIMARILY IN THE LOWER 40S. LOW LEVEL
THERMALS COMBINED WITH MODEST BOUNDARY LAYER MIXING SUPPORT A NICE
AFTERNOON WITH HIGHS RISING INTO THE LOWER AND MID 60S.
LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 148 PM EST SAT NOV 16 2024
SUNDAY NIGHT THROUGH TUESDAY.
MUCH WARMER THAN NORMAL TEMPERATURES WILL CONTINUE INTO MONDAY WITH
BROAD RIDGING ACROSS THE OHIO VALLEY AND STRENGTHENING SOUTHERLY
FLOW NEAR THE SURFACE AS A LOW PRESSURE SYSTEM MOVES ACROSS SOUTHERN
CANADA. HIGHS ON MONDAY AND TUESDAY WILL CLIMB INTO THE LOW TO MID
60S WITH SOME UPPER 60S POSSIBLE SOUTH OF INDIANAPOLIS ON TUESDAY.
CLOUD COVER WILL GRADUALLY BEGIN TO INCREASE LATE MONDAY AS THE NEXT
RAIN PRODUCING SYSTEM BEGINS TO MOVE NORTHEASTWARD FROM THE BAJA
PENINSULA INTO THE PLAINS.
THE LOW PRESSURE SYSTEM ACROSS CANADA WILL HELP TO PUSH THE SYSTEM
IN A MORE NORTHERLY DIRECTION THAN WOULD TYPICALLY BE EXPECTED OF A
SYSTEM TRACKING FROM THE BAJA PENINSULA. THIS WILL KEEP THE HEAVIEST
RAIN WEST OF THE FORECAST AREA WITH PRECIPITATION ONSET LATE MONDAY
NIGHT. THE GREATER IMPACTS FROM THIS SYSTEM WILL BE FROM GRADIENT
WINDS TUESDAY AS THE BOUNDARY LAYER DEEPENS TO AROUND 4KFT WHICH
WILL ALLOW THE MIXING DOWN OF WINDS TO AROUND 25-35 MPH. TOTAL
RAINFALL IS EXPECTED TO BE AROUND A QUARTER OF AN INCH.
WEDNESDAY THROUGH SATURDAY.
THE MOST IMPACTFUL WEATHER OF THE FORECAST PERIOD IS EXPECTED
WEDNESDAY NIGHT INTO THURSDAY AS THE TUESDAY SYSTEM CONTINUES TO
MOVE NORTHWARD. A MUCH STRONGER LOW PRESSURE SYSTEM WILL UNDERGO
CYCLOGENESIS AS IT MOVES IN FROM THE NORTHWEST IN THE AFTERMATH OF
THE FIRST SYSTEM. THIS LOW WILL BE ABLE TO INTEGRATE SOME OF THE
WARMER AND MORE MOIST AIR FROM THE PREVIOUS SYSTEM WHICH WILL
FURTHER ENHANCE THE PRECIPITATION AS IT NEARS THE OHIO VALLEY. A LOW
TRACKING IN THIS GENERAL DIRECTION WOULD TYPICALLY WOULD BE MORE
STARVED OF MORE ROBUST MOISTURE WITH A LACK OF A GOOD SOURCE. THERE
REMAINS A LOT OF UNCERTAINTY AS TO BOTH THE TRACK AND STRENGTH OF
THE LOW, BUT CONFIDENCE IS INCREASING THAT AT LEAST PARTS OF THE
FORECAST AREA WILL SEE THE FIRST SNOWFLAKES OF THE YEAR WITH THE
POTENTIAL FOR MINOR ACCUMULATIONS.
SURFACE TEMPERATURES WEDNESDAY NIGHT INTO THURSDAY WILL BE MARGINAL
AT BEST (32-35) WHICH COMBINED WITH THE VERY WARM GROUND TEMPS WILL
HELP TO LIMIT THE TOTAL SNOWFALL, BUT THERE IS A GOOD SIGNAL FOR A
TIGHTER BAND OF PRECIPITATION ON THE NORTHERN END OF THE LOW WHICH
WOULD BE ABLE TO OVERCOME THE GROUND TEMPERATURES IF THE COLDER-END
MODEL SOLUTIONS VERIFY AND SNOW MIXES IN. THERE IS ALSO SOME
QUESTION AS TO HOW QUICKLY THE COLDER AIR MOVES IN WITH THE
POTENTIAL THAT THE BULK OF THE FORCING MAY EXIT BEFORE THE NEAR
SURFACE AIR IS COLD ENOUGH TO SUPPORT SNOWFALL. MODEL SNOW
ACCUMULATIONS WILL CONTINUE TO SEVERELY STRUGGLE IN THESE MARGINAL
TEMPERATURE WITH HIGH QPF SCENARIOS WITH MODEL SNOW DEPTH NUMBERS
SHOWING 20-50% OF THE TOTAL ACCUMULATION VALUES WHICH BETTER FACTOR
IN THE MARGINAL GROUND AND NEAR SURFACE TEMPERATURES.
WHERE CONFIDENCE IS HIGHER IS THAT THURSDAY WILL BE A DREARY AND
COLD DAY WITH WIND GUSTS OF 30-40 MPH, WIDESPREAD CLOUD COVER, AND
TEMPERATURES THAT WILL LIKELY STAY BELOW 40. LAKE ENHANCED MOISTURE
WILL CONTINUE TO STREAM INTO THE NORTHEASTERN COUNTIES FRIDAY INTO
SATURDAY WHICH MAY BRING ADDITIONAL CHANCES FOR LIGHT SNOW ALONG
WITH WIDESPREAD COLDER THAN NORMAL CONDITIONS ACROSS ALL OF CENTRAL
INDIANA THROUGH THE WEEKEND INTO EARLY THE FOLLOWING WEEK.
AVIATION (06Z TAF ISSUANCE)
ISSUED AT 202 AM EST SUN NOV 17 2024
IMPACTS:
- CAN NOT RULE OUT MVFR TO IFR STRATUS LATE SUNDAY NIGHT
DISCUSSION:
CENTRAL INDIANA WILL LARGELY SIT UNDER THE BACKSIDE OF A SURFACE
HIGH BRINGING SOUTHERLY TO SOUTHWESTERLY WINDS TODAY AND INTO
TONIGHT. WINDS WILL START OFF AROUND 5 TO 10 KTS DUE TO TIGHTER
PRESSURE GRADIENTS. BY THE EVENING INTO THE OVERNIGHT HOURS AN
APPROACHING WARM FRONT WILL BRING LOW CLOUDS AROUND THE END OF THE
TAF PERIOD AND INTO THE 24+ HR FOR IND THAT COULD DROP CEILINGS AS
LOW AS IFR LATE TONIGHT. WINDS WILL ALSO DROP TO NEAR CALM TONIGHT.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...MK
SHORT TERM...RYAN
LONG TERM...WHITE
AVIATION...KF
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