327
FXUS63 KIND 141920
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
220 PM EST THU NOV 14 2024
KEY MESSAGES
- ISOLATED TO SCATTERED BRIEF SHOWERS THROUGH EARLY EVENING.
- CLOUDY THROUGH EARLY SATURDAY THEN PARTIAL CLEARING.
- RAIN CHANCES RETURN TUESDAY FOLLOWED BY A TREND TOWARD COOLER
TEMPERATURES BY THE END OF THE WEEK.
SHORT TERM (THIS EVENING THROUGH FRIDAY)
ISSUED AT 220 PM EST THU NOV 14 2024
IN THE WAKE OF DEPARTING TROUGH, ADVECTION IS GENERALLY NEUTRAL. LOW-
LEVEL MOISTURE IS STILL PRESENT AS IS EVIDENT IN SATELLITE IMAGERY
WITH BROAD AREA OF LOW STRATUS. LOWER TROPOSPHERIC MOISTURE DEPTH
AND STEEPENING LOW-LEVEL LAPSE RATES MAY BE ENOUGH FOR SHALLOW
CONVECTIVE SHOWERS INTO THE EVENING. THESE OFTEN HAVE SMALL DROPS
AND ARE MORE LIKE DRIZZLE, THOUGH THEY CAN BE HEAVIER AND MORE
INTERMITTENT. COVERAGE/INTENSITY SHOULD DECREASE THIS EVENING, BUT
STRATUS WILL PERSIST THROUGH TOMORROW. WE HAVE LOWERED TEMPERATURES
SLIGHTLY TOMORROW AS WE EXPECT SIMILAR CONDITION TO TODAY WITH
PERSISTENT STRATUS LIMITING SURFACE HEATING.
LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 220 PM EST THU NOV 14 2024
FOG INITIALLY SEEMED AT LEAST POSSIBLE FRIDAY NIGHT INTO SATURDAY
MORNING, BUT STRATUS LOOKS TO PERSIST INTO THIS PERIOD. LOW LEVEL
MOISTURE TRAPPED BENEATH A STRONG SUBSIDENCE INVERSION THIS TIME OF
YEAR OFTEN RESULTS IN PROLONGED STRATUS. ON THE WESTERN EDGE OF THE
STRATUS, FOG IS MORE LIKELY, BUT THIS NOW APPEARS TO BE IN ILLINOIS
OR MISSOURI. WITH PBL MOISTURE BECOMING LESS AND MIXING ON SATURDAY,
STRATUS IS LIKELY TO BREAK AROUND MIDDAY. BY THEN, MID-HIGH CLOUDS
FROM THE UPSTREAM SYSTEM AND PACIFIC MOISTURE PLUME, IN ADDITION TO
INCREASINGLY MSLP GRADIENT SHOULD LIMIT POTENTIAL FOG SUNDAY
MORNING.
WE WILL BE ON THE WINDWARD SIDE OF PROGRADING MEAN RIDGE AXIS
SUNDAY, SO TEMPERATURES WILL BE ABOUT 10 DEGREES ABOVE MID-NOVEMBER
CLIMO. WE STILL HAVE LOW PROBABILITIES OF RAIN FOR PORTIONS OF THE
AREA SUNDAY NIGHT INTO EARLY MONDAY, BUT TRENDS IN ALMOST ALL OF THE
ENSEMBLE MODELS HAVE BEEN FOR LESS COVERAGE AND FURTHER NORTH. THIS
IS TIED TO A TREND TOWARD A LESS AMPLIFIED NORTHERN STREAM SHORTWAVE
TROUGH. THERE IS STILL MODEST MOISTURE RETURN INDICATED IN THE
MODELS AND ASCENT WITH A MIDLEVEL THERMAL GRADIENT, SO WILL LEAVE
SLIGHT CHANCE IN.
STILL WARM MONDAY AND TUESDAY AS RIDGING RESURGES PRECEDING THE NEXT
SYSTEM. THERE IS LIMITED ENSEMBLE SPREAD ON LEAD SHORTWAVE TROUGH
PASSING TO OUR NORTHWEST TUESDAY. ITS ASSOCIATED WARM CONVEYER
BELT/MOISTURE SURGE SHOULD BRING A BAND OF RAIN MONDAY NIGHT AND
EARLY TUESDAY, BUT COLD ADVECTION WILL BE MINIMAL AS THIS TROUGH
WEAKENS AND MOVES EAST AT THE SAME TIME DIGGING TROUGH EVOLVES OVER
THE PLAINS.
WEDNESDAY ONWARD WE WILL ENTER A PERIOD OF LOW-MID RANGE
PRECIPITATION PROBABILITIES AND COLDER TEMPERATURES. THE SYNOPTIC-
SCALE PATTERN IS STILL SOMEWHAT UNCERTAIN AS EPS-WEIGHTED CLUSTERS
HOLD THE PLAINS TROUGH WEST LONGER, WHILE GFS IS DEEPER AND MORE
PROGRESSIVE. THIS MAY PRIMARILY IMPACT TEMPERATURES WEDNESDAY AS THE
FORMER CAMP OFFERS AN OPPORTUNITY TO WARM PRIOR TO THE ONSET OF
STRONGER COLD ADVECTION, COMPARED TO THE LATTER CAMP. DETAILS WITH
REGARDS TO PERIODS OF ENHANCED FORCING/ASCENT WITH ROTATING
VORTICITY MAXIMA ARE UNCLEAR. ALSO, COLD ADVECTION MAGNITUDE APPEARS
TO BE MODULATED BY SUBSTANTIAL HIGH-LATITUDE RIDGING IN THIS
BLOCKING PATTERN, SO WHETHER OR NOT TEMPERATURES ARE COLD ENOUGH FOR
SNOW LATE NEXT WEEK IS NOT TOTALLY CLEAR. TEMPERATURES WILL BE
MARGINAL. STEEP LAPSE RATES BENEATH THE COLD CORE LOW WOULD SUPPORT
A MORE SHOWERY REGIME.
DAY 8-14 WILL START OFF WITH TROUGHING, AND THERE APPEARS TO BE SOME
SIGNAL FOR THIS TO PERSIST. NEAR TO BELOW NORMAL TEMPERATURES
AND NEAR NORMAL PRECIPITATION WOULD RESULT.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 1213 PM EST THU NOV 14 2024
IMPACTS:
- MVFR/IFR CONDITIONS WILL CONTINUE
- SOME VISIBILITY REDUCTION DUE TO MIST/DRIZZLE POSSIBLE THROUGH MID-
AFTERNOON
DISCUSSION:
MVFR TO IFR CEILINGS WILL PREVAIL, LIKELY THROUGH THE END OF THE TAF
PERIOD. DELINEATING SPECIFIC TIMES A SITE WILL BE ON EITHER SIDE OF
THE MVFR/IFR THRESHOLD WILL BE DIFFICULT, BUT IT DOES APPEAR THAT
THE LOWEST CEILINGS MAY BE THROUGH LATE AFTERNOON, AND ONLY
IMPROVING SLIGHTLY LATER TONIGHT. EVEN LATER TONIGHT THROUGH
TOMORROW MORNING, IFR CANNOT BE RULED OUT. WINDS WILL VEER ABOUT 30-
40 DEGREES DURING THE COURSE OF THE TAF PERIOD.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...BRB
LONG TERM...BRB
AVIATION...BRB
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