388
FXUS63 KIWX 191121
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
621 AM EST TUE NOV 19 2024
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES EXPECTED THE NEXT 24 HOURS BEFORE
MUCH COLDER ARRIVES STARTING WEDNESDAY NIGHT AND LINGERING
INTO THE WEEKEND.
- SHOWERS WILL QUICKLY EXIT BY MORNING WITH A PERIOD OF DRY
CONDITIONS LIKELY UNTIL WEDNESDAY AFTERNOON INTO AT LEAST
FRIDAY.
- A MIXTURE OF RAIN AND SNOW IS EXPECTED WITH THE MAIN POTENTIAL
FOR SOME WET SNOWFLAKES AND MAYBE MINOR ACCUMULATIONS ON
ELEVATED SURFACES COMING LATE WED NIGHT INTO THURSDAY.
DISCUSSION
ISSUED AT 349 AM EST TUE NOV 19 2024
WELL DEFINED UPPER LOW AND ASSOCIATED SFC LOW WAS MOVING INTO SW
MINNESOTA. THE UPPER LEVEL LOW WILL CONTINUE TO FILL AND BECOME
ABSORBED IN THE APPROACHING NORTHERN STREAM TROUGH THAT WILL QUICKLY
DEEPEN. THE SURFACE LOW WILL CONTINUE PUSHING NORTH, REACHING
NORTHERN MN THIS AFTERNOON. LIFT WITH THE WARM FRONT HAS PUSHED WELL
NORTH OF THE AREA WITH OUR FOCUS A RAPIDLY MOVING BAND OF SHOWERS
NOW MORE THAN HALF WAY ACROSS THE FORECAST AREA. A FEW STORMS
DEVELOPED ON THE LEADING EDGE, BUT HAVE SINCE DISSIPATED WITH
POCKETS OF LIGHT TO MODERATE RAIN OCCURRING IN THE BAND. BACK EDGE
OF THE SHOWERS WILL MOST LIKELY BE CLEAR OF THE AREA BY 12Z. THE
AREA WILL BECOME SEPARATED FROM THE BETTER LIFT AND MOISTURE AS THE
MAIN UPPER LOW TAKES SHAPE TO THE NW AND DIVES SE INTO THE REGION BY
WEDNESDAY NIGHT. THIS SHOULD LEAD TO A 24 TO MAYBE 30 HOUR PERIOD OF
LITTLE OR NO RAINFALL. PLENTY OF 60S NOTED UPSTREAM SET TO MOVE INTO
THE AREA THIS MORNING, BUT THAT WILL BE THE LAST OF THE WARM
TEMPERATURES FOR A WHILE. ONE OTHER ITEM TO NOTE BEFORE GOING TO
COLDER AIR ARRIVAL IS GUSTY WINDS BEHIND THE AREA OF RAIN AND AHEAD
OF THE COLD FRONT. SOME GUSTS HAVE ALREADY OCCURRED IN THE 25 TO 30
KT RANGE. EXPECTING THIS TO CONTINUE THROUGH THE MORNING SO HAVE
INCREASED WINDS SOMEWHAT.
EVOLUTION OF THE UPPER LOW IN THE WED THROUGH FRI PERIOD SEEMS TO BE
LINING UP BETTER WITH THE LOW TRAVELLING FROM MINNESOTA AT 18Z WED
TO LOWER MI 12Z THU AND THEN DIVING SOUTH INTO VA BY 00Z FRI. WHILE
MUCH COLDER AIR ARRIVES WED NIGHT INTO THUR THAT WOULD LIKELY LEAD
TO POTENTIAL FOR SOME SNOW, MANY FINER DETAILS REMAIN TO BE SORTED
OUT THAT WILL IMPACT PTYPE AND ACCUMULATIONS. HAVE KEPT WITH A MIX
OF RAIN/SNOW NORTHERN PARTS OF THE AREA LATE WED NIGHT INTO THURS
WHERE WET BULB TEMPS WILL STAY ABOVE FREEZING. SOUTHERN PORTIONS OF
THE AREA STAND THE BEST CHANCE OF SEEING JUST SNOW, BUT THESE SAME
AREAS ALSO MAY SEE THE LOWEST CHANCES FOR PRECIP AS THE MAIN AREA
REMAINS FURTHER NORTH WITH THE UPPER LOW. ALTHOUGH FORECAST GRIDS
SHOW UP TO AN INCH OF SNOW ACROSS SOUTHERN AREAS LATE WED NIGHT INTO
THURSDAY AM, THIS IS LIKELY OVERDONE AS ANY ACCUMULATION WOULD
LIKELY MELT ON THE WARMER GROUND. NO TRAVEL CONCERNS ARE EXPECTED.
THE BEST CHANCE FOR PRECIPITATION OCCURS AS A STRONG WAVE ROTATES
NORTH TO SOUTH ACROSS THE AREA MAINLY THURS AFTERNOON AND NIGHT. NBM
HAS BEEN RATHER QUICK ON BRINGING POPS INTO NORTHERN AREAS (AS EARLY
AS WED NIGHT/EARLY THUR) BUT AT THIS POINT TEMPERING POPS SOMEWHAT
INITIALLY. BY THIS POINT, WARMER (ALBEIT IT STILL SUB ZERO 850 MB
AIR) WILL MOVE IN WITH THE WAVE KEEPING PRECIP EITHER RAIN OR A
RAIN/SNOW MIX.
PERIODIC WAVES WILL PASS THROUGH THE NW FLOW AS THE THROUGH SATURDAY
BEFORE THE LOW FINALLY MOVES NE AND INCREASING HEIGHTS ARRIVE. NO
CHANGES MADE TO LATER PERIODS.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 620 AM EST TUE NOV 19 2024
OCCLUDED FRONT IS CURRENTLY APPROACHING THE TERMINALS AND WILL
BRING A BRIEF PERIOD OF IFR CEILINGS DURING THE NEXT FEW HOURS.
INCREASING DRY AIR ADVECTION AND MIXING WILL CAUSE A TRANSITION
TO HIGH-END MVFR BY LATE MORNING BUT CHANCES FOR VFR APPEAR LOW
UNTIL LATE THIS AFTERNOON GIVEN A THIN SATURATED LAYER AT THE
BASE OF THE INVERSION ON FORECAST SOUNDINGS. ANOTHER ROUND OF
STRATUS AND FOG/BR IS POSSIBLE WED MORNING BUT PRIMARY IMPACTS
STILL APPEAR JUST OUTSIDE THIS FORECAST WINDOW.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-
046.
DISCUSSION...FISHER
AVIATION...AGD
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