327
FXUS63 KIWX 211723
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1223 PM EST FRI FEB 21 2025
KEY MESSAGES
* CLOUDS DECREASE FROM WEST TO EAST TODAY WITH HIGH TEMPERATURES
IN THE UPPER 20S.
* MAINLY DRY CONDITIONS EXPECTED THROUGH THE WEEKEND WITH A
MODERATING TEMPERATURE TREND THAT WILL CONTINUE INTO EARLY NEXT
WEEK.
* THE NEXT RAIN CHANCE ARRIVES BY MONDAY NIGHT/TUESDAY, BUT ONLY
LIGHT RAINFALL AMOUNTS EXPECTED.
DISCUSSION
ISSUED AT 335 AM EST FRI FEB 21 2025
REMNANTS OF THE LAKE MODIFIED LOW LEVEL TROUGHING PERSISTS EARLY
THIS MORNING ACROSS NORTHEAST INDIANA/NORTHWEST OHIO, BUT LARGE
SCALE SUBSIDENCE IS RESULTING IN INCREASINGLY LIMITED MOISTURE
DEPTHS. A FEW FLURRIES MAY PERSIST A FEW MORE HOURS ACROSS THE
NORTHEAST, WITH POSSIBLY EVEN A LITTLE BIT OF NON-IMPACTFUL VERY
LIGHT DRIZZLE. SOME FAIRLY STRONG MID LEVEL SUBSIDENCE HAS
DEVELOPED IN RESPONSE TO DEPARTING LARGER SCALE UPPER TROUGH
ACROSS EASTERN CONUS AND SHORT WAVE RIDGING BUILDING IN ACROSS
THE NORTHERN GREAT LAKES. CLEARING LINE HAS ENTERED WESTERN
PORTIONS OF THE FORECAST AREA EARLY THIS MORNING AND SHOULD
PROGRESS EASTWARD TO THE INTERSTATE 69 CORRIDOR LATER THIS
MORNING. STILL SOME UNCERTAINTY IN REGARDS TO HOW QUICKLY SKIES
WILL CLEAR PARTICULARLY ACROSS SOUTH CENTRAL LOWER MICHIGAN INTO
EXTREME NE INDIANA/NW OHIO WITH SOME POSSIBLE SLOWING TO THE
CLEARING AS DAYTIME HEATING MAY INTERACT WITH LINGERING SHALLOW
MOISTURE TO SLOW CLEARING. LOW LEVEL THERMAL RIDGE WILL ALSO BE
A BIT SLOWER TO BUILD INTO THESE LOCATIONS. NO SIGNIFICANT
CHANGE MADE TO PREVIOUS FORECASTED HIGHS IN THE UPPER 20S ACROSS
THE AREA. AREAS WITH LESS SNOW COVER ACROSS THE WEST MAY
APPROACH 30, WHILE AREAS WITH DEEPER FRESHER SNOWPACK FROM
YESTERDAY'S LAKE EFFECT SNOW MAY BE HELD MORE INTO THE MID 20S
WITH POOR MIXING IN VICINITY OF LOW LEVEL RIDGE AXIS MOVING
ACROSS THE REGION.
MINS TONIGHT WILL BE SOMEWHAT TRICKY GIVEN LOW LEVEL AIRMASS
MODERATION CONTINUING. NEW SNOWPACK AND FAIRLY GOOD RADIATIONAL
COOLING CONDITIONS WILL LIKELY OFFSET THIS MODERATION FOR MINS BACK
INTO THE LOWER TEENS TONIGHT. SOME WEAK LOW LEVEL RETURN
SOUTHWESTERLY FLOW WITH EASTWARD DEPARTURE OF THE RIDGE AXIS
SHOULD PREVENT TEMPS FROM BOTTOMING OUT TOO MUCH ACROSS THE
NORTHWEST DESPITE THE NEW SNOWCOVER.
ON SATURDAY A CUT-OFF UPPER LEVEL TROUGH IN SOUTHERN STREAM OF SPLIT
FLOW PATTERN ACROSS WESTERN CONUS WILL OPEN AND BECOME POSITIVELY
TILTED ACROSS THE MID MS RIVER VALLEY. AN AXIS OF DRY LOW LEVEL
AIR DOWNSTREAM OF THE NORTHERN STREAM UPPER RIDGING WILL LIMIT
ANY MOISTURE AVAILABILITY WITH THIS SOUTHERN STREAM TROUGH. THE
MAIN IMPACT LOCALLY FROM THIS SOUTHERN STREAM TROUGH WILL BE TO
SLOW THE TEMPERATURE MODERATION A BIT FOR SATURDAY.
SUNDAY AND MONDAY WILL BE CHARACTERIZED BY A LOW AMPLITUDE MID/UPPER
LEVEL FLOW PATTERN WITH STOUT WEST-NORTHWEST MID/UPPER FLOW THAT
WILL SUPPORT A SERIES OF WEAK PACIFIC WAVES TRACKING ACROSS THE
GREAT LAKES. THE STRONG ZONAL COMPONENT WILL ALSO SUPPORT A SHARPER
MODERATING TEMPERATURE TREND HEADING INTO SUNDAY AND MONDAY. THE
FIRST OF THESE PACIFIC WAVES SHOULD BE TAKE A TRACK NORTH OF
THE LOCAL AREA, WITH BETTER SURGE OF PACIFIC MOISTURE LIKELY
BYPASSING THE LOCAL AREA TO THE NORTH. CAN'T COMPLETELY RULE
OUT SOME LOW CHANCE OF LIGHT RAIN OR DRIZZLE ACROSS THE FAR
NORTH LATE SUNDAY NIGHT INTO EARLY MONDAY, BUT THIS CHANCE
APPEARS MINIMAL AT THIS TIME. HIGHS SUNDAY SHOULD REACH WELL
INTO THE 30S AREA-WIDE, AND INTO THE 40S OR EVEN LOWER 50S FAR
WEST/SOUTHWEST FOR MONDAY.
PASSAGE OF THIS LEAD WAVE TO THE NORTH MONDAY WILL SUPPRESS HEIGHTS
A BIT LOCALLY THAT SHOULD ALLOW NEXT PACIFIC WAVE TO TAKE A MORE
SOUTHERN TRACK MORE FAVORABLE FOR ADDITIONAL PRECIP CHANCES
MONDAY NIGHT/EARLY TUESDAY. DETERMINISTIC/ENSEMBLE GUIDANCE IN
SOME DECENT AGREEMENT REGARDING THIS WAVE WHICH SHOULD BE
ACCOMPANIED BY A BIT BETTER MOISTURE. HOWEVER, PROGRESSIVE
NATURE OF THIS PATTERN AND OVERALL LIMITED DURATION OF DEEPER
MOISTURE PROFILES SHOULD RESULT IN ONLY LIGHT RAINFALL AMOUNTS.
SOME INDICATIONS IN MEDIUM RANGE GUIDANCE OF AT LEAST A POTENTIAL OF
A STRONGER SHORT WAVE TROUGH TOWARD LATE WED/THU. HOWEVER, GIVEN
HIGHLY PROGRESSIVE NATURE TO THIS PATTERN, WILL CONFINE ANY
TWELVE HOUR POP PERIOD TO JUST MID/HIGH CHANCE WITH
TIMING/STRENGTH UNCERTAINTIES. LARGE SCALE FLOW AMPLIFICATION BY
THIS TIME ALSO LEADS TO SOME POTENTIAL OF A COLD AIR INTRUSION
ACROSS NORTHERN PLAINS/GREAT LAKES TOWARD END OF THE PERIOD AND
THUS WILL MAINTAIN CHANCE OF RAIN WED TRANSITIONING TO CHANCE OF
RAIN/SNOW LATER THU.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1222 PM EST FRI FEB 21 2025
WITH SOUTHWEST WINDS AND HIGH PRESSURE MOVING THROUGH EXPECT A
RETURN TO VFR CONDITIONS FOR BOTH SITES. SUNNY SKIES PREVAIL TODAY,
BUT A FEW TO SCATTERED HIGH CLOUDS MAY MOVE IN ON SATURDAY. MIXING
IS EXPECTED TO STAY MINIMAL WITH THOSE HIGH CLOUDS AROUND SATURDAY,
BUT WITH A LOW LEVEL JET MOVING THROUGH, GUSTS BETWEEN 15 AND 25 KTS
WILL BECOME MORE COMMON DURING THE AFTERNOON.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...ROLLER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page