071
FXUS63 KIWX 101029
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
529 AM EST FRI JAN 10 2025
KEY MESSAGES
- SNOW ARRIVES FROM WEST TO EAST STARTING MID MORNING. 2 TO 4
INCHES IS EXPECTED. THE EVENING COMMUTE WILL BE IMPACTED.
- LAKE EFFECT SNOW TONIGHT THROUGH SATURDAY MORNING.
- VERY COLD EARLY NEXT WEEK WITH BELOW-ZERO WIND CHILLS AND
ADDITIONAL CHANCES FOR SNOW.
DISCUSSION
ISSUED AT 320 AM EST FRI JAN 10 2025
THE WINTER WEATHER FORECAST FOR TODAY REMAINS ON TRACK WITH
WIDESPREAD 2 TO 4 INCHES OF SNOW EXPECTED. THE WINTER WEATHER
ADVISORY WAS A BYPRODUCT OF NEIGHBORING OFFICES HOISTING ADVISORIES.
THE MORNING COMMUTE WILL NOT BE IMPACTED. HOWEVER, ANTICIPATE A SLOW
EVENING COMMUTE. SNOW BEGINS MID MORNING TOWARD MICHIANA AND ENDS
AFTER THE EVENING RUSH. TOWARD NORTHWEST OHIO, SNOW BEGINS ON EITHER
SIDE OF NOON, TAPERING OFF NEAR MIDNIGHT.
A POSITIVE-TILTED TROUGH IS EXITING THE DAKOTAS THIS MORNING WHILE A
SECOND, DEEPER, TROUGH IS EJECTING NORTHEAST OUT OF TEXAS. UPPER-
LEVEL CONVERGENCE IS SPILLING OVER THE MID-MISSISSIPPI VALLEY
ALLOWING RADAR RETURNS TO BLOSSOM THERE. THE 500-MB JET IS
FORECAST TO AMPLIFY OVER THE TENNESSEE RIVER VALLEY THIS
AFTERNOON AND WILL BE THE PRIMARY DRIVER OF OUR SNOW TODAY. DEW
POINTS CURRENTLY IN THE SINGLE-DIGITS NEED TO BE OVERCOME. AMID
THIS BUCKED JET STREAM, MOISTURE ADVECTION IS POSITIVE AS NOTED
BY DEW POINTS IN THE MID-TO- UPPER TEENS FROM CHICAGO SOUTHWARD.
TIME HEIGHT CROSS SECTIONS INDICATE FAVORABLE FRONTOGENESIS BY
LATE MORNING WHICH WILL WORK TO OVERCOME WHAT SHALLOW WEDGE OF
DRY AIR REMAINS.
JUST AS THIS SNOW TAPERS OFF, THE LAGGING DAKOTAS TROUGH RACES
THROUGH AFTER SUNSET AND PROVIDES ANOTHER PERIOD OF LIGHT SNOW.
BECAUSE OF ITS SWIFT FORWARD PACE, THIS TROUGH WILL BRING
LITTLE ADDITIONAL ACCUMULATION BUT BREEZY CONDITIONS WILL
DEVELOP TONIGHT AS WILL LAKE EFFECT. WIND GUSTS WILL BE FROM THE
WEST AT ABOUT 20 MPH.
BEYOND THIS BUSY 24 HOUR PERIOD, AN ACTIVE UPPER-AIR PATTERN BRING
MULTIPLE DISTURBANCES THROUGH THE REGION. CLIPPER SYSTEMS, LAKE
EFFECT SNOW AND ARCTIC AIR ARE ALL EXPECTED IN THE DAYS AHEAD. FIRST,
FREEZING DRIZZLE WAS ADDED TO THE FORECAST SUNDAY AS THE NEXT LOW
PRESSURE SYSTEM MOVES OVER THE GREAT LAKES. WHILE THE THERMAL
PROFILE OVERALL IS SUPPORTIVE OF SNOW, DEEP SATURATION IS SLOW TO
OCCUR. AS A RESULT, THE LOW-LEVEL SATURATES BELOW THE DGZ FAVORING
FREEZING DRIZZLE. THROUGH THE DAY, A TRANSITION TO SNOW IS EXPECTED.
THIS WILL NEED TO BE MONITORED CLOSELY.
THEN, AN ARCTIC FRONT RACES IN MONDAY NIGHT AND TUESDAY MORNING
BRINGING ANOTHER CHANCE FOR LIGHT SNOW FOLLOWED BY BITTER COLD.
WIND CHILLS TUESDAY AND WEDNESDAY MORNING WILL BE BELOW ZERO.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 525 AM EST FRI JAN 10 2025
MOISTURE ADVECTION FROM THE SOUTHWEST WILL CONTINUE THIS MORNING
AND INCREASED ISENTROPIC LIFTING AHEAD OF THE INCOMING SYSTEM
TO MOVE IN LATER THIS MORNING, MAINLY AFTER 13Z FRI FOR KSBN AND
AFTER 14Z FRI FOR KFWA, BRINGING PERIODS OF LIGHT TO MODERATE
SNOWFALL THROUGH THIS EVENING WITH 2-4" OF ACCUMULATION WITH
THIS STORM. CIGS WILL CONTINUE TO LOWER OVER THE NEXT COUPLE OF
HOURS TO MVFR LEVELS AND BECOMING IFR AT TIMES BY THIS
AFTERNOON AT BOTH TAF SITES. PERIODS OF VSBY DROPPING BELOW 1SM
THIS AFTERNOON WITH THE HEAVIER SNOW SHOWERS/BURSTS. SNOW WILL
TAPER OFF THIS EVENING HOWEVER MVFR IN RESIDUAL LOWERED CIGS
SHOULD PERSIST THROUGH THE REMAINDER OF THIS TAF PERIOD.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 1 AM EST /MIDNIGHT CST/ SATURDAY FOR INZ005>009-
012>015-017-018-020-022>027-032>034-103-104-116-203-204-
216.
OH...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 AM EST
SATURDAY FOR OHZ001-002-004-005-015-016-024-025.
MI...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 AM EST
SATURDAY FOR MIZ078>081-177-277.
MARINE...NONE.
DISCUSSION...BROWN
AVIATION...ANDERSEN
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