917
FXUS63 KIND 270746
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
324 AM EDT THU MAR 27 2025
KEY MESSAGES
- SHOWERS INCREASE THIS AFTERNOON WITH THE HIGHEST CHANCES ACROSS
SOUTH CENTRAL INDIANA
- SHOWERS AND THUNDERSTORMS EXPECTED TONIGHT FOR THE ENTIRE REGION.
A FEW STORMS MAY BE STRONG WITH SMALL HAIL AS A PRIMARY THREAT.
- SEASONABLY WARM FRIDAY-SUNDAY WITH HIGHS INTO THE 70S THEN TURNING
COOLER EARLY NEXT WEEK
- WET AND UNSETTLED PATTERN DEVELOPING WITH PERIODIC RAIN AND STORM
CHANCES THURSDAY THROUGH MONDAY
- STRONG TO SEVERE STORMS EXPECTED SUNDAY AFTERNOON AND EVENING
SHORT TERM (TODAY AND TONIGHT)
ISSUED AT 324 AM EDT THU MAR 27 2025
A SHIFT TOWARD A MUCH WARMER AND WETTER WEATHER PATTERN OCCURS OVER
THE NEXT 24 HOURS ACROSS MUCH OF THE MIDWEST AND OHIO VALLEY WHICH
WILL LARGELY PERSIST INTO EARLY APRIL.
LATEST SATELLITE IMAGERY CLEARLY DEPICTS WHATS LEFT OF THE
NORTHWESTERLY FLOW PATTERN THAT HAS BEEN OVER THE MIDWEST THE PAST
WEEK. A MID AND UPPER LEVEL DISTURBANCE CHARACTERIZED BY WIDESPREAD
HIGH CLOUDS STRETCHES FROM THE DAKOTAS SOUTHEASTWARD INTO INDIANA
AND KENTUCKY. ALOFT, A STRONG NORTHWESTERLY JET REMAINS OVERHEAD,
BUT WILL BE SHIFTING EAST OVER THE NEXT 24 HOURS AS RIDGING BUILDS
INTO THE REGION AND OVERALL FLOW SWITCHES TO THE WEST/SOUTHWEST.
RADAR IMAGERY DOES SHOW SCATTERED SHOWERS UPSTREAM UNDER THE MID TO
HIGH LEVEL CLOUDS IN ILLINOIS; HOWEVER WITH SUCH DRY AIR FROM AROUND
THE SURFACE UP TO 600MB, MOST OF THE PRECIPITATION IS NOT REACHING
THE GROUND. SENSIBLE IMPACTS FROM THESE WEAK DISTURBANCES WILL ONLY
BE INCREASED CLOUDS AND ELEVATED TEMPERATURES OVERNIGHT AS CLOUDS
INHIBIT RADIATIONAL COOLING OF THE SURFACE. INCREASED TEMPERATURES
THIS MORNING FOR THE SOUTHWEST 2/3RDS OF CENTRAL INDIANA DUE TO
THESE CLOUDS, KEEPING LOWS IN THE UPPER 30S TO LOWER 40S.
DURING THE DAY, THE WEATHER PATTERN WILL UNDERGO THE WELL ADVERTISED
PATTERN SHIFT AS LOW LEVEL RIDGING PUSHING EAST, RESULTING IN FLOW
TO BECOME SOUTHWESTERLY WITH INCREASING MOISTURE ADVECTION INTO THE
REGION. A WARM FRONTAL FEATURE SETS UP JUST SOUTHWEST OF THE STATE
AS LOW PRESSURE DEVELOPS OFF THE FRONT RANGE OF THE ROCKIES. WEAK
DISTURBANCES ALOFT IN ADDITION TO THE DEVELOPING FRONT WILL PROVIDE
ENOUGH LIFT FOR ADDITIONAL SHOWERS TO DEVELOP IN SOUTH CENTRAL AND
SW INDIANA DURING THE DAY TODAY. MAIN FOCUS FOR SHOWER DEVELOPMENT
WILL LIKELY BE ALONG AND SOUTHWEST OF THE I-74 CORRIDOR, CLOSEST TO
THE WARM FRONT AND WHERE STRONGEST FORCING FOR ASCENT AND SATURATION
WILL BE. LOWER CONFIDENCE EXISTS IN HOW FAR NORTH THE MORE
WIDESPREAD SHOWER ACTIVITY WILL MAKE IT, INCLUDING FOR THE INDY
METRO AREA. DO EXPECT THESE SHOWERS TO EVENTUALLY PUSH FURTHER
NORTH AND EAST ACROSS THE REGION, BUT NOT LIKELY UNTIL THIS EVENING
OR TONIGHT. KEEPING HIGHS BELOW NBM25TH PERCENTILE, IN THE LOW TO
MID 50S, ALONG AND SOUTHWEST OF THE I-74 CORRIDOR DUE TO THE
INCREASE IN SHOWER COVERAGE TODAY. WHILE CLOUDS WILL BE INCREASING
FURTHER NORTH AND EAST, DRIER AIR AND LOWER RAIN CHANCES MAY ALLOW
FOR TEMPERATURES TO REACH THE MID TO UPPER 50S FOR PORTIONS OF
CENTRAL AND NORTHEAST INDIANA.
TONIGHT
STRONG WARM AND MOIST AIR ADVECTION INCREASES ALOFT TONIGHT AIDED BY
A 40-50 KT LOW LEVEL SOUTHWESTERLY JET DEVELOPING OVERHEAD. WITH THE
WARM FRONT SLOWLY MAKING ITS WAY NORTH AND EAST INTO CENTRAL
INDIANA, THE ATMOSPHERIC PROFILE WILL SUPPORT NUMEROUS TO WIDESPREAD
SHOWER AND THUNDERSTORM ACTIVITY GOING INTO THE OVERNIGHT HOURS.
STRONG WARM AIR ADVECTION ALOFT WILL RESULT IN STEEPENING MID AND
UPPER LEVEL LAPSE RATES ABOVE A SURFACE TEMPERATURE INVERSION. HI-
RES MODEL GUIDANCE SHOWS UPWARDS OF 500+ J/KG OF ELEVATED CAPE ALONG
THE WARM FRONT TONIGHT IN ADDITION TO 40-50 KTS OF SHEAR, MAKING FOR
AN ENVIRONMENT CONDUCIVE FOR ELEVATED THUNDERSTORMS. POTENTIAL IS
THERE FOR SMALL HAIL WITH THIS SET UP , ESPECIALLY WITH SUCH DRY AIR
ALOFT, SO WILL HAVE TO WATCH FOR STRONG TO ISOLATED SEVERE STORMS
TONIGHT.
LONG TERM (FRIDAY THROUGH WEDNESDAY)
ISSUED AT 324 AM EDT THU MAR 27 2025
A MUCH WARMER AND WETTER WEATHER PATTERN CONTINUES INTO THE LONG
TERM...WITH ONLY BRIEF COOL DOWNS BEHIND FRONTAL PASSAGES. CHANCES
FOR SEVERE WEATHER RAMP UP AS WELL WITH ENHANCED FOCUS ON SUNDAY.
FRIDAY AND SATURDAY...
AFTER A ROUND OF THUNDERSTORMS DURING THE EARLY MORNING HOURS
FRIDAY, THE WARM FRONT PASSES NORTHWARD OF THE REGION RESULTING IN A
MUCH DRIER DAY AND WARMER DAY AHEAD. STRONG WARM AIR ADVECTION AND
SOLAR INSOLATION WILL LEAD TO WELL ABOVE AVERAGE TEMPERATURES BY
FRIDAY AFTERNOON. INCREASED TEMPERATURES TOWARD THE NBM75TH
PERCENTILE AS DEEP LOW LEVEL MIXING AND STRONG SURFACE HEATING WILL
LIKELY RESULT IN HIGHS EXCEEDING GUIDANCE INTO THE MID AND UPPER
70S. WOULD NOT BE SURPRISED IF A LOCATION OR TWO HITS THE 80 DEGREE
MARK IN SOUTH CENTRAL AND WESTERN INDIANA. ALSO, WITH SUCH A STRONG
LOW LEVEL JET ALOFT, EXPECT HIGHER WIND GUSTS UP TO OR OVER 40 MPH
TO MIX DOWN TO THE SURFACE DURING PEAK HEATING OF THE DAY. INCREASED
WIND GUSTS TO REFLECT THIS, HOWEVER IF THIS TREND CONTINUES IN LATER
FORECAST ISSUANCES... THEN WIND HEADLINES MAY BE NEEDED.
DRY CONDITIONS SHOULD CONTINUE INTO FRIDAY NIGHT WITH THE NEXT ROUND
OF SHOWERS AND STORMS SATURDAY AFTERNOON INTO SATURDAY NIGHT. A MID
TO UPPER LEVEL DISTURBANCE WITHIN THE WARM SECTOR WILL SPARK OFF
NUMEROUS SHOWERS SATURDAY AFTERNOON AND INTO THE OVERNIGHT HOURS.
ATMOSPHERIC PROFILES LOOK PRETTY STABLE DURING THIS PERIOD WITH WEAK
LAPSE RATES, SO NOT TOO CONCERNED WITH SEVERE WEATHER. PRIMARY
THREAT WILL BE REPEATED ROUNDS OF HEAVY RAIN AND AND ISOLATED
LIGHTNING STRIKE. TOTAL QPF WITH THIS LOW PRESSURE SYSTEM MAY BE AS
HIGH AS AN INCH BUT EXACT DETAILS ARE FAIRLY UNCERTAIN.
SATURDAY WILL BE VERY WARM AS WELL, BUT WITH INCREASING CLOUDS AND
SHOWERS, HIGHS LIKELY WILL REMAIN IN THE UPPER 60S TO LOWER 70S.
THERE IS SOME TIMING DISCREPANCIES AMONG GUIDANCE FOR WHEN SHOWERS
ARRIVE... WITH A LATER ARRIVAL TIME OF RAIN RESULTING IN WARMER
TEMPERATURES DURING THE DAY.
SUNDAY THROUGH WEDNESDAY...
*POTENTIAL FOR ALL MODES OF SEVERE WEATHER SUNDAY*
A MUCH STRONGER SYNOPTICALLY DRIVEN LOW PRESSURE SYSTEM IS EXPECTED
LATE SUNDAY INTO SUNDAY NIGHT WITH THE POTENTIAL FOR STRONG TO
SEVERE STORMS TO IMPACT CENTRAL INDIANA WITH HIGHER CONFIDENCE IN
IMPACTS ACROSS THE OHIO VALLEY IN GENERAL. GLOBAL MODELS AND THEIR
ASSOCIATED ENSEMBLES SHOW DECENT AGREEMENT IN THE BROADER TROUGH AND
ASSOCIATED COLD FRONT WITH DIFFERENCES ON BOTH THE STRENGTH AND
TIMING OF THE LOW PRESSURE SYSTEM. THUS THERE IS HIGH CONFIDENCE IN
PRECIPITATION WITH LOWER CONFIDENCE IN TIMING AND INTENSITY OF THE
ASSOCIATED THUNDERSTORMS. THERE HAS BEEN AGREEMENT ON A FEW
PARAMETERS WITHIN THIS SET UP, SUCH AS LARGELY SOUTHWEST FLOW AT THE
SURFACE AND ALOFT ON SUNDAY LEADING TO MORE UNIDIRECTIONAL SHEAR
THROUGH THE COLUMN. SUFFICIENT CAPE AND SHEAR THROUGH THE COLUMN
WITH MORE ELONGATED HODOGRAPHS MAY RESULT IN AN ENVIRONMENT MORE
CONDUCIVE FOR A DAMAGING WIND THREAT RATHER THAN A WIDESPREAD
TORNADO THREAT. NOT TO DOWN PLAY THE TORNADO THREAT AT ALL, AS A FEW
ARE CERTAINLY POSSIBLE. BUT CURRENTLY CONFIDENCE IS HIGHER IN
STRAIGHT LINE WINDS WITH STORMS. WILL DIVE MORE INTO THE DETAILS OF
SUNDAY'S SEVERE WEATHER THREAT OVER THE NEXT FEW DAYS AS CONFIDENCE
AND AGREEMENT AMONG GUIDANCE INCREASES.
COLDER AIR WILL MOVE IN BEHIND THE EXITING LOW SUNDAY NIGHT WITH SUB-
FREEZING TEMPERATURES LIKELY FOR AT LEAST PART OF THE FORECAST AREA
MONDAY NIGHT. DRY WEATHER WITH NORTHERLY SURFACE FLOW WILL THEN
CONTINUE THROUGH TUESDAY WITH A SHIFT TO EASTERLY FLOW TOWARDS
WEDNESDAY AS RAIN CHANCES BEGIN TO INCREASE ALTHOUGH THE OVERALL
SYNOPTIC PATTERN IS HIGHLY UNCERTAIN.
AVIATION (06Z TAF ISSUANCE)
ISSUED AT 155 AM EDT THU MAR 27 2025
IMPACTS:
- MVFR CIGS AND LIGHTING CHANCES INCREASE TOWARD THE END OF THE TAF
PERIOD
DISCUSSION:
SURFACE HIGH PRESSURE OVER INDIANA IS EXPECTED TO PUSH EAST TO THE
CAROLINAS TONIGHT AND TOMORROW. THE HIGH WILL ALLOW FOR LIGHT WINDS
ACROSS THE TAF SITES TONIGHT WITH SOUTHERLY FLOW DEVELOPING ON
THURSDAY.
GOES16 SHOWS MID LEVEL CLOUDS PUSHING INTO INDIANA FROM THE
NORTHWEST, HOWEVER CONFIDENCE IS HIGH THAT CEILINGS WILL REMAIN VFR
THROUGH AT LEAST THE REST OF THE NIGHT AND INTO THE MORNING HOURS.
SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED TO DEVELOP THIS AFTERNOON
AND PERSIST INTO THE OVERNIGHT HOURS TONIGHT AND FRIDAY. DUE TO SUCH
DRY MID AND LOWER LEVELS, CIGS WILL LIKELY REMAIN VFR THIS AFTERNOON
DESPITE SHOWER ACTIVITY. HOWEVER FOR TONIGHT AND TOWARD THE END OF
THE TAF PERIOD, CONTINUED SATURATION OF THE LOWER LEVELS AND
PERSISTENT SHOWER ACTIVITY AROUND MAY RESULT IN CEILINGS DROPPING TO
MVFR LEVELS.
ADDITIONALLY, OVERNIGHT TONIGHT AND INTO EARLY FRIDAY MORNING, THE
CHANCES FOR LIGHTNING INCREASE. DID NOT MENTION IT IN THE TAF AS
CONFIDENCE IS LOW IN EXACTLY WHERE AND WHEN LIGHTNING WILL OCCUR.
WHILE THE PATTERN CERTAINLY SUPPORTS THUNDERSTORMS, WILL UPDATE THE
TAF WITH THUNDER WORDING IN LATTER ISSUANCES WHEN CONFIDENCE GROWS
ON EXACT DETAILS OF TIMING AND PLACEMENT OF THESE MESOSCALE
FEATURES.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...CM
LONG TERM...CM
AVIATION...CM
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