437
FXUS63 KIWX 230001
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
701 PM EST FRI NOV 22 2024
KEY MESSAGES
- A CHANCE OF LIGHT LAKE EFFECT RAIN OR DRIZZLE INTO TONIGHT BUT
ANY PRECIP AMOUNTS WILL BE LIGHT.
- MODERATING TEMPERATURES THIS WEEKEND INTO EARLY NEXT WEEK
WITH HIGHS IN MID 50S BY MONDAY.
- RAIN CHANCES RETURN SUNDAY NIGHT INTO MONDAY. CONFIDENCE
REMAINS LOWER ON MIDWEEK PRECIP CHANCES.
DISCUSSION
ISSUED AT 355 PM EST FRI NOV 22 2024
LOCAL AREA REMAINS POSITIONED IN UPPER LEVEL INFLECTION ZONE THIS
AFTERNOON BETWEEN BROAD WESTERN CONUS UPPER RIDGE AND LARGE UPPER
LOW ACROSS EASTERN CONUS. THIS PATTERN HAS MAINTAINED FAVORABLE
NORTHERLY FETCH FOR LIGHT LAKE EFFECT RAIN/DRIZZLE, BUT MOISTURE
DEPTHS APPEAR TO HAVE BEEN LIMITING FACTOR THIS AFTERNOON FOR
COVERAGE. SOME SUBTLE BACKING OF LOW LEVEL WINDS IS ANTICIPATED
TONIGHT AS LOW LEVEL ANTICYCLONE DROPS ACROSS THE LOWER MS
VALLEY. THIS SHOULD TEND TO LIMIT ADDITIONAL LAKE EFFECT PRECIP.
ONE POSITIVE FACTOR FOR CONTINUED LAKE EFFECT LIGHT RAIN COULD
BE SOME MODEST INCREASE IN MID LEVEL MOISTURE AFTER DAYBREAK
SATURDAY. HOWEVER BY THIS TIME, FETCH WILL BE FURTHER REDUCED
AND SHOULD CONTINUE TO LIMIT ADDITIONAL MEASURABLE PRECIP
CHANCES AFTER TONIGHT.
FOR SATURDAY, LOW CLOUDS MAY TEND TO DISSIPATE WITH EVOLUTION TO A
MORE BACKED LOW LEVEL FLOW. HOWEVER, MID AND HIGH CLOUDS SHOULD
INCREASE DURING THE AFTERNOON AS ZONE OF STRONG MID LEVEL WARM
ADVECTION ACCOMPANIES THE EASTWARD PROGRESSION OF MID LEVEL
RIDGE AXIS. TEMPERATURES SHOULD BE FAIRLY SIMILAR TO THAT
OBSERVED TODAY AS CONTINUED MODERATION IN LOW LEVEL THERMAL
PROFILES IS OFFSET BY GOOD DEAL OF CLOUD COVER AND MORE SHALLOW
MIXING HEIGHTS IN COMPARISON TO TODAY.
FOR SUNDAY AND MONDAY, A STRONG EASTERN PACIFIC JET WILL PUSH INTO
THE NORTHERN ROCKIES EVENTUALLY CARVING OUT AN UPPER HEIGHT MINIMUM
AS A MORE SUBSTANTIAL UPPER LEVEL WAVE TRACKS ACROSS THE NORTHERN
PLAINS SUNDAY NIGHT. BROAD WARM/MOIST ADVECTION WILL STRENGTHEN
SATURDAY NIGHT THROUGH SUNDAY NIGHT IN ADVANCE OF THIS WAVE. SEVERAL
FACTORS STILL SUPPORT HIGH CHANCE/LOW LIKELY POPS DURING THIS PERIOD
INCLUDING FAVORABLE POSITIONING TO APPROACHING EASTERN PAC JET
STREAK, MATURING FRONTAL FORCING, AND AT LEAST BRIEF SURGE OF
ANOMALOUS LOW LEVEL MOISTURE INTO THE REGION. THIS PATTERN WILL BE
QUITE PROGRESSIVE WHICH WILL LIMIT RAINFALL AMOUNTS. SOME BRIEF,
WEAK LAKE RESPONSE IS POSSIBLE BEHIND THIS WAVE FOR TUESDAY, BUT
INSTABILITY DEPTHS SHOULD BE ON A SHARP DECLINE. CONFIDENCE REMAINS
HIGH IN TREND BACK TO BELOW NORMAL TEMPERATURES FOR TUESDAY.
FORECAST CONFIDENCE FOR THE THANKSGIVING PERIOD POTENTIAL PRECIP
REMAINS ON THE LOW SIDE. MEDIUM RANGE GUIDANCE HINTS AT A BIT OF A
SPLIT-NATURE OF FLOW ACROSS PACIFIC NORTHWEST WITH A COMPLICATED
WAVE EVOLUTION BETWEEN SOUTHERN/NORTHERN STREAMS. WITH SUCH GREAT
UNCERTAINTY IN BUDGETING STRENGTHS OF NORTHERN/SOUTHERN STREAM
AND TIMING DISCREPANCIES BETWEEN FASTER GEFS/SLOWER EPS
NORTHERN STREAM EVOLUTION, HAVE JUST MAINTAINED BROADBRUSH MID-
HIGH CHANCE RAIN/SHOWER POPS FOR NOW FOR WED NIGHT THROUGH
FRIDAY. CONFIDENCE REMAINS A BIT HIGHER IN REGARDS TO CONTINUED
BELOW NORMAL TEMPERATURES THOUGH THE EXTENDED PERIOD.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 641 PM EST FRI NOV 22 2024
PREDOMINANTLY MVFR TO VFR CONDITIONS ARE EXPECTED AT THE
TERMINALS. LIGHT LAKE EFFECT DRIZZLE WILL CONTINUE TO DIMINISH
OVERNIGHT AS SUBSIDENCE FROM THE INCOMING HIGH BUILDS IN AND
WINDS SHIFT MORE WESTERLY. IFR IS POSSIBLE, BUT DIDN'T HAVE
ENOUGH CONFIDENCE TO PUT IN THE TAF. NORTHWEST WIND GUSTS WILL
BE INTERMITTENT OVERNIGHT, THEN BECOME MORE FREQUENT DURING THE
DAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST SATURDAY FOR LMZ043-046.
DISCUSSION...MARSILI
AVIATION...MCD
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