831  
FXUS63 KIND 181936  
AFDIND  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE INDIANAPOLIS IN  
236 PM EST MON NOV 18 2024  
   
KEY MESSAGES  
 
- RAIN TONIGHT ALONG WITH GUSTS 25 TO 35 MPH  
 
- RAIN ENDS TUESDAY MORNING, THEN A WARM AND DRY AFTERNOON  
 
- MUCH COLDER WEATHER WEDNESDAY NIGHT THROUGH SATURDAY WITH SNOW  
LIKELY NORTHEAST OF INDIANAPOLIS, LITTLE TO NO ACCUMULATIONS  
 
- BREEZY WEDNESDAY AND THURSDAY AFTERNOONS WITH GUSTS OF 25-35 MPH  
 
 
   
SHORT TERM (THIS EVENING THROUGH TUESDAY)  
 
ISSUED AT 236 PM EST MON NOV 18 2024  
 
INITIAL ROUND OF ISENTROPIC LIFT WILL CONTINUE TO PUSH NORTH THIS  
AFTERNOON, TAKING THE RAIN WITH IT. WILL KEEP SOME POPS AS NEEDED IN  
THE NORTH FOR THE REMAINDER OF THE AFTERNOON, DIMINISHING WITH TIME.  
 
SATELLITE SHOWS SOME BREAKS IN THE CLOUDS HAVE DEVELOPED SOUTH OF  
THE AREA, AND THESE WILL MOVE INTO AT LEAST THE SOUTHERN AREA. THIS  
SUNSHINE PLUS CONTINUED WARM ADVECTION WILL KEEP TEMPERATURES WARM  
THIS AFTERNOON.  
 
CENTRAL INDIANA WILL BE IN A LULL BETWEEN AREAS OF FORCING THIS  
EVENING, SO WILL GO DRY DURING THE EVENING HOURS. OVERNIGHT THE WARM  
CONVEYOR BELT WILL MOVE INTO THE AREA. 850MB WINDS OF 50-60KT WILL  
BRING IN PLENTIFUL MOISTURE. A POTENT SYSTEM MOVING INTO THE UPPER  
MISSISSIPPI VALLEY WILL PROVIDE GOOD FORCING TO INTERACT WITH THIS  
MOISTURE. THUS, EXPECT SOME RAIN TO FALL ACROSS THE AREA FROM WEST  
TO EAST DURING THE NIGHT. WILL GO HIGH POPS ALL AREAS.  
 
GIVEN THE STRONG WINDS ALOFT AND LITTLE OR NO INVERSION BELOW, SOME  
GUSTS WILL OCCUR AT THE SURFACE. HI-RES MODELS LOOK TO BE OVERDOING  
GUSTS AS USUAL (SHOWING 50 MPH GUSTS), BUT ENSEMBLES DO SHOW PEAK  
WINDS NEARING 40 MPH IN THE WESTERN FORECAST AREA TONIGHT.  
CONVECTION WILL BE POSSIBLE BUT NOT DEEP OR WIDESPREAD GIVEN VERY  
LOW INSTABILITY EXPECTED.  
 
GIVEN THE LACK OF NOTABLE CONVECTION, THE LOWER PEAK GUSTS OF THE  
ENSEMBLES SEEM MORE REASONABLE. STRONGEST GUSTS WILL BE ACROSS THE  
WESTERN FORECAST AREA WHERE THE STRONGER WINDS ALOFT WILL BE.  
 
WITH THE SURFACE COLD FRONT REMAINING WEST OF THE AREA TONIGHT, LOWS  
WILL BE VERY WARM FOR THIS TIME OF NOVEMBER, WITH LOWS IN THE MIDDLE  
50S TO NEAR 60. RECORD HIGH MINIMUMS FOR NOVEMBER 19 WILL NOT BE IN  
JEOPARDY THOUGH AS COLDER AIR WILL MOVE DURING THE EVENING HOURS OF  
TUESDAY.  
 
SOME RAIN MAY LINGER EARLY TUESDAY BEFORE DRIER AIR MOVES IN ALOFT,  
SO WILL KEEP SOME LOW POPS EARLY, DIMINISHING AS THE MORNING  
PROGRESSES. SOME DRYING WILL OCCUR IN THE LOWER LEVELS, BUT THERE IS  
A CONCERN OF SOME LOWER CLOUDS REDEVELOPING NORTH WITH SOME COLDER  
AIR ALOFT MOVING IN. WILL KEEP SKIES PARTLY CLOUDY NORTH GIVEN THIS  
POSSIBILITY.  
 
WITH COLDER AIR AT THE SURFACE HOLDING BACK UNTIL LATER IN THE DAY,  
TEMPERATURES ON TUESDAY WILL BE WARM AGAIN, WITH HIGHS IN THE MIDDLE  
TO UPPER 60S EXPECTED.  
 
 
   
LONG TERM (TUESDAY NIGHT THROUGH MONDAY)  
 
ISSUED AT 236 PM EST MON NOV 18 2024  
 
TUESDAY NIGHT THROUGH THURSDAY.  
 
BY TUESDAY NIGHT THE LOW PRESSURE SYSTEM THAT WILL BRING WIDESPREAD  
RAIN TO INDIANA TONIGHT WILL HAVE FULLY OCCLUDED AS IT CONTINUES TO  
TRACK NORTH INTO CANADA. THE VORT MAX ASSOCIATED WITH THE OCCLUDED  
LOW WILL QUICKLY GET INGESTED INTO THE JET STREAM AND BEGIN TO SHIFT  
BACK SOUTHEASTWARDS. THE TRACK OF THE SURFACE LOW ASSOCIATED WITH  
THE UPPER LEVEL SYSTEM CONTINUES TO SLOWLY TREND NORTHEASTWARD WITH  
ENSEMBLES NOW CLUSTERING ON A SLIGHTLY WEAKER AND MORE NORTHEASTERLY  
TRACK WHICH WAS THE OUTLIER THIS TIME YESTERDAY.  
 
STRONGER CYCLOGENESIS IS EXPECTED TO KICK OFF WEDNESDAY INTO  
WEDNESDAY NIGHT ACROSS MICHIGAN WITH A RAPIDLY STRENGTHENING LLJ  
SOUTHWEST OF THE PARENT LOW PRESSURE SYSTEM. RAINFALL LOOKS LIKELY  
ACROSS THE NORTHEASTERN COUNTIES WEDNESDAY AFTERNOON IN RESPONSE TO  
THIS STRENGTHENING LLJ WITH MORE WIDESPREAD PRECIPITATION WEDNESDAY  
NIGHT INTO THURSDAY ON THE BACKEND OF THE SYSTEM AS THE LOW  
CONTINUES TO DEEPEN AND ANOTHER JET STREAK IN THE MID LEVELS PUSHES  
SOUTHWARD. THESE MINOR CHANGES IN THE FORECAST TRACK AND STRENGTH  
ARE ALSO CREATING A TIGHTER GRADIENT ON WHERE PRECIPITATION IS  
EXPECTED TO FALL GOING INTO THURSDAY WITH THE POTENTIAL THAT SPOTS  
NEAR AND SOUTHWEST OF INDIANAPOLIS ONLY SEE FLURRIES WHILE AREAS TO  
THE NORTHEAST SEE SNOW SHOWERS. SURFACE TEMPERATURES WEDNESDAY NIGHT  
INTO THURSDAY WILL BE MARGINAL AT BEST WHICH COMBINED WITH THE VERY  
WARM GROUND TEMPS SHOULD ANY SNOW ACCUMULATIONS, BUT WITH DECENT  
NEAR SURFACE LAPSE RATES THERE MAY BE SHORT PERIODS WHERE SNOWFALL  
RATES MAY OVERCOME THE WARMER TEMPERATURES.  
 
WIND CHILLS THURSDAY MAY DROP INTO THE UPPER TEENS WITH THE  
COMBINATION OF WIND GUSTS TO 35 MPH AND TEMPERATURES IN THE 30S  
WHICH WILL FEEL EVEN COLDER WITH THE RECENT WARMNESS.  
 
FRIDAY THROUGH MONDAY.  
 
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 INTO THE EARLY WEEKEND. CONDITIONS  
WILL REMAIN BREEZY FRIDAY AFTERNOON AS PRESSURE GRADIENTS REMAIN  
TIGHT. BY SUNDAY THE FLOW WILL BECOME MORE ZONAL WHICH WILL FAVOR  
THE CLEARING OUT OF THE NEAR SURFACE STRATUS AND GRADUALLY WARMING  
TEMPERATURES.  
 
FORECAST CONFIDENCE QUICKLY FALLS OF SUNDAY INTO MONDAY WITH MAJOR  
DIFFERENCES IN DETERMINISTIC MODELS AND A WIDE SPREAD IN ENSEMBLE  
SPAGHETTI PLOTS AS MODELS STRUGGLE IN HANDLING A CLIPPER SYSTEM  
ACROSS CANADA AND HOW IT WILL INTERACT WITH A BROAD RIDGE OF HIGH  
PRESSURE ACROSS THE APPALACHIANS. THERE ARE SOME SIGNS THAT THE  
CLIPPER SYSTEM WILL BE STRONG ENOUGH TO PUSH INTO THE OHIO VALLEY  
WHICH WOULD BRING A COLD FRONT AND A RETURN TO RAIN CHANCES, BUT  
CONFIDENCE IS LOW AT THIS POINT. WHERE CONFIDENCE IS HIGHER IS THAT  
TEMPERATURES WILL GRADUALLY WARM SUNDAY INTO MONDAY WITH A RETURN IN  
ABOVE NORMAL HIGHS AND LOWS.  
 
 
   
AVIATION (18Z TAF ISSUANCE)  
 
ISSUED AT 1201 PM EST MON NOV 18 2024  
 
IMPACTS:  
 
- MVFR CIGS THROUGH 21Z  
- OCCASIONAL MVFR TO IFR VSBYS DUE TO RAIN THROUGH 21Z, AGAIN AFTER  
06Z THROUGH 09Z  
- LLWS 06Z TO 10Z  
- SOUTHEASTERLY WIND GUSTS TO 20KTS AFTER 03Z  
 
DISCUSSION:  
 
MVFR CIGS WILL CONTINUE TO SLOWLY IMPROVE TO VFR THIS AFTERNOON AS  
RAIN MOVES THROUGH. RAIN COVERAGE WILL BE HIGHEST AT LAF AND HUF  
WITH MINIMAL RAIN AT IND AND BMG. VSBYS WILL REMAIN VFR OUTSIDE OF  
THE HEAVIEST SHOWERS. ADDITIONAL RAIN WILL MOVE IN TONIGHT AFTER 06Z  
ALONG WITH A STRONG LLJ WHICH WILL BRING LLWS. CIGS ARE EXPECTED TO  
DROP BACK TO MVFR AFTER THE RAIN COMES TO AN END. WINDS WILL REMAIN  
LIGHT THROUGH THE DAY TODAY BEFORE SOUTHEASTERLY GUSTS OF 20KTS  
BEGIN AFTER 03Z WITH THE STRONGEST WINDS LIKELY BETWEEN 09Z AND 14Z.  
 
 
   
IND WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
SHORT TERM...50  
LONG TERM...WHITE  
AVIATION...WHITE  
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