358
FXUS63 KIWX 191437
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
937 AM EST SAT JAN 19 2019
SYNOPSIS
ISSUED AT 404 AM EST SAT JAN 19 2019
HAZARDOUS WINTER WEATHER IS EXPECTED TODAY, WITH WIDESPREAD SNOW
BECOMING MODERATE TO HEAVY AT TIMES. WIND GUSTS UP TO 30 TO 35 MPH
ARE EXPECTED, LEADING TO BLOWING AND DRIFTING SNOW. HIGHS WILL BE IN
THE 20S. LOWS TONIGHT WILL DROP INTO THE SINGLE DIGITS, WITH WIND
CHILLS AS COLD AS 10 BELOW ZERO. EXPECT MOSTLY CLOUDY SKIES WITH
HIGHS IN THE TEENS SUNDAY, WITH A CHANCE FOR LAKE EFFECT IN FAR
NORTHWESTERN INDIANA.
UPDATE
ISSUED AT 927 AM EST SAT JAN 19 2019
SOME MINOR CHANGES WILL BE MADE TO WSW THIS MORNING. SOME FREEZING
RAIN HAS BEEN REPORTED ACROSS EXTREME NORTHEAST INDIANA/NORTHWEST
OHIO THIS MORNING WITH INITIAL SATURATION ISSUES AT TEMPERATURES
COLD ENOUGH TO SUPPORT SNOW PRODUCTION. BETTER MOISTURE WILL
OVERSPREAD THESE AREAS OVER NEXT FEW HOURS THAT WOULD SUPPORT MORE
SNOW PRECIP TYPES, ALTHOUGH SOME CONCERN THAT WARM LAYER ADVECTING
NORTHEASTWARD COULD SUPPORT ADDITIONAL SLEET/FREEZING RAIN
ACROSS THESE LOCATIONS. WILL ADD SOME ICE ACCUMULATION TO FAR
SOUTHEAST/EAST ZONES WITH THE WSW UPDATE. HAVE ALSO NUDGED
QPF/SNOW AMOUNTS UP SLIGHTLY ACROSS EASTERN HALF OF THE AREA THIS
AFTERNOON WITH SUPPORT FROM LATEST NEAR TERM HRRR/NAM GUIDANCE.
INTERACTIONS OF NORTHERN/SOUTHERN STREAM WAVE SHOULD PROMOTE
INCREASED LOW/MID LEVEL FGEN FORCING THIS AFTERNOON PARTICULARLY
SOUTHEAST HALF OF THE FORECAST AREA. REGIONAL RADAR MOSAIC APPEARS
TO ALREADY INDICATE THE BEGINNINGS OF THIS RESPONSE FROM EAST
CENTRAL ILLINOIS INTO WEST CENTRAL INDIANA. IT STILL APPEARS AS
THOUGH A PERIOD OF STRONG WIND GUSTS TO 35 MPH (PERHAPS GREATER)
IS POSSIBLE ACROSS THE SOUTHEAST LATER THIS AFTERNOON INTO TONIGHT
WHICH WILL CREATE CONSIDERABLE TRAVEL DIFFICULTIES. ONLY OTHER
CHANGE WILL BE SLIGHT ALTERATIONS IN ENDING TIMES OF WINTER STORM
WARNING TO LATER EXPIRATIONS, PARTICULARLY ACROSS THE FAR
SOUTHEAST ZONE WHERE STRONGER WINDS AND BLOWING AND DRIFTING SNOW
WILL BE A CONCERN POSSIBLY INTO THE OVERNIGHT HOURS. UPDATED WSW
WILL BE SENT BY 15Z.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 404 AM EST SAT JAN 19 2019
NO CHANGES TO WINTER STORM HEADLINES THIS MORNING. IT APPEARS
HEADLINES ARE ON TRACK, AGAIN WITH THE FOCUS ON THE WIND AND SNOW
COMBINATION VERSUS SOLELY SNOW AMOUNTS. THE FIRST PORTION OF THE
FORECAST HAS WORKED OUT (KNOCK ON WOOD), WITH THE SNOW ASSOCIATED
WITH THE MID-UPPER LEVEL FGEN SITUATED NORTH OF I 80-90. SO FAR
WE'VE RECEIVED REPORTS BETWEEN 1-2 INCHES ASSOCIATED WITH THIS.
WINDS HAVE ALSO PICKED UP TO AROUND 10-15KTS ACROSS THE CWA.
OTHERWISE, SNOW ASSOCIATED WITH OUR SOUTHERN STREAM SYSTEM IS
CONTINUING NORTHWARD, AND WILL OVERSPREAD THE AREA THROUGH THE
MORNING AND AFTERNOON HOURS. MODELS CONTINUE TO SHOW THE
STRENGTHENING DEFORMATION FORCING THIS AFTERNOON, AND THINK THIS IS
REASONABLE BASED ON WHAT WE'RE SEEING THIS MORNING. WIND GUSTS WILL
STRENGTHEN INTO THE 25 TO 35 MPH RANGE, SO ONCE WE GET ADDITIONAL
SNOW ACCUMULATIONS WE'LL SEE THE BLOWING AND DRIFTING BECOME MORE OF
AN ISSUE FOR TRAVEL.
MUCH COLDER AIR FILTERS IN BEHIND OUR WINTER STORM, WHICH EXITS THE
FAR SOUTHEASTERN CWA BY LATE THIS EVENING. EXPECT MAYBE AN INCH OF
ADDITIONAL ACCUMULATION IN THE SOUTHEAST, WITH PARTLY TO MOSTLY
CLOUDY SKIES ELSEWHERE. MODELS SUGGEST 850MB TEMPS DROPPING TO
AROUND -15C, AND WITH SOME BRIEF CLEARING IN THE WAKE OF THE LOW,
EXPECT LOW TEMPS INTO THE SINGLE DIGITS BY EARLY SUNDAY MORNING.
WIND CHILLS WILL RANGE FROM 0 TO 10 BELOW.
LONG TERM
(SUNDAY THROUGH FRIDAY)
ISSUED AT 404 AM EST SAT JAN 19 2019
ON SUNDAY HIGH PRESSURE EXPANDS OVER MUCH OF THE GREAT LAKES REGION,
BUILDING TO AROUND 1039 HPA. WITH NORTHEAST FLOW ACROSS LAKE
MICHIGAN AND LINGERING MOISTURE EXPECT OUR TRADITIONAL LAKE EFFECT
BAND TO DEVELOP ALONG THE LONG AXIS OF THE LAKE, IMPACTING THE
CHICAGO AND FAR NW INDIANA LOCATIONS DURING THE EARLY PART OF THE
DAY. THE UPPER LEVEL LOW OVER SOUTHERN ONTARIO AND QUEBEC WILL DROP
ONE LAST VORT LOBE OVER THE REGION BY LATE SUNDAY AFTERNOON AND
EVENING, WHICH WILL BRING THE LAKE EFFECT POTENTIAL INTO OUR AREA.
GUIDANCE APPEARS TO BE TRYING TO DEVELOP A MESOLOW AT THE SOUTHERN
END OF THE LAKE, WHICH WOULDN'T BE TOTALLY UNREASONABLE GIVEN THE
WIND DIRECTION/WEAK SYNOPTIC SUPPORT. MOISTURE IS LIMITED HOWEVER,
SO DON'T EXPECT TOO MUCH IN THE WAY OF ACCUMULATIONS. HAVE LOWER
CONFIDENCE WITH RESPECT TO HOW FAR EASTWARD THE BAND/MESOLOW WILL
DRIFT AT THIS POINT TOO, SO JUST KEPT LOW CHANCE POPS IN FROM SUNDAY
AFTERNOON INTO THE EVENING HOURS. WITH 850HPA TEMPS AROUND -20C AND
MOSTLY CLOUDY SKIES, DON'T EXPECT HIGHS TO REACH BEYOND THE TEENS,
WITH WIND CHILLS IN THE SINGLE DIGITS ABOVE ZERO DURING THE
AFTERNOON.
THE REAL HORROR WILL TAKE PLACE AS SKIES CLEAR OUT SUNDAY NIGHT INTO
MONDAY MORNING AWAY FROM LAKE MICHIGAN: WITH A FRESH SNOWPACK AND
LIGHT WINDS BENEATH HIGH PRESSURE, EXPECT THAT IT WILL GET
EXTRAORDINARILY COLD. LOW TEMPERATURES BY MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS BELOW ZERO, WITH SOME PLACES IN NW OHIO
AROUND -8F. WINDS WILL BE LIGHT, BUT COULD BE ENOUGH TO BRING WIND
CHILLS INTO THE -10 TO -15F RANGE. EVEN WITH PARTLY CLOUDY SKIES
DURING THE DAY ON MONDAY, HIGHS WILL PROBABLY ONLY RANGE FROM 10-16F
BY THE AFTERNOON (WIND CHILLS AROUND OR JUST BELOW ZERO). MONDAY
NIGHT LOWS WILL FALL INTO THE SINGLE DIGITS AND LOW TEENS, WITH WIND
CHILLS FROM 0 TO 10 BELOW (COLDEST EAST OF I 69). CONDITIONS WILL
REMAIN DRY THROUGH EARLY TUESDAY MORNING.
OUR NEXT PRECIPITATION CHANCES ARRIVE TUESDAY AFTERNOON INTO
WEDNESDAY EVENING AS A LOW PRESSURE SYSTEM LIFTS FROM THE CENTRAL
PLAINS INTO THE GREAT LAKES REGION. MODELS APPEAR TO BE CLOSE IN
TERMS OF THE TIMING OF PRECIPITATION, THOUGH THEY VARY GREATLY IN
THE INTENSITY OF THE SYSTEM (GFS HAS 1003HPA, ECMWF HAS 1010 HPA.
NATURALLY THIS BRINGS SOME DISAGREEMENT AS FAR AS THE OVERALL QPF
AMOUNTS/LOCATIONS GO. THE GOOD NEWS IS THAT 850HPA TEMPS CLIMB TO
AROUND 2-3C SO WE START TO SEE HIGHS IN THE MID-UPPER 30S TUESDAY
AFTERNOON. THIS WILL GIVE US A RAIN/SNOW MIX DURING THE AFTERNOON
AND EVENING HOURS TUESDAY BEFORE SHIFTING BACK TO SNOW OVERNIGHT.
THERE MAY BE A LITTLE LAKE EFFECT DURING THE AFTERNOON WEDNESDAY
BEFORE SUBSIDENCE AND A LACK OF MOISTURE PUT AN END TO IT.
OTHERWISE, EXPECT DWINDLING SNOW CHANCES IN THE SOUTHEAST ASSOCIATED
WITH THE EXITING SYSTEM. HIGHS WILL BE IN THE UPPER 20S AND 30S.
WEDNESDAY NIGHT INTO THURSDAY EVENING WILL MOST LIKELY BE DRY, WITH
OUR CWA UNDER A MINI-RIDGE OF HIGH PRESSURE BETWEEN A STRONGER LOW
LIFTING ALONG THE EASTERN SEABOARD AND A WEAKER LOW DRIFTING ACROSS
UPPER MICHIGAN. THERE IS A CHANCE WE COULD SEE SOME PRECIPITATION
ACROSS OUR SOUTHEAST BUT CONFIDENCE IN THIS OCCURRING IS LOW. HIGHS
WILL BE IN THE UPPER 20S UNDER MOSTLY CLOUDY SKIES.
THURSDAY NIGHT INTO FRIDAY THE EAST COAST LOW LIFTS INTO QUEBEC,
PHASING WITH THE WEAKER LOW OVER UPPER MICHIGAN ALONG THE WAY. THIS
MAKES FOR AN INTERESTING FORECAST, WITH SYNOPTIC SNOW POTENTIAL
INITIALLY THURSDAY NIGHT INTO FRIDAY MORNING, THEN TRANSITIONING TO
MORE OF A LAKE EFFECT SNOW FOR FRIDAY AFTERNOON. THE UPPER LEVEL LOW
SITUATED OVER JAMES BAY WILL BRING ANOTHER TROUGH (OR SURFACE LOW,
DEPENDING ON YOUR FAVORITE MODEL) THROUGH FRIDAY NIGHT INTO
SATURDAY, WITH POTENTIAL FOR 850HPA TEMPS TO DROP TO -20 TO EVEN
-25C BY SATURDAY NIGHT...POTENTIALLY WORSENING SUNDAY INTO MONDAY.
LONG STORY SHORT, IT LOOKS LIKE WE'LL SEE ANOTHER SHOT OF VERY COLD
AIR TOWARDS THE END OF THE LONG TERM PERIOD.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 600 AM EST SAT JAN 19 2019
STRONG LOW LEVEL WARM ADVECTION/MOISTURE PUSH UNDERWAY THIS HOUR
CORRESPONDING TO MAXIMIZING ISENTROPIC LIFT AHEAD OF BIFURCATED
UPPER TROUGH AXIS PROGRESSING OUT OF IL. WEDGE OF LOW LEVEL DRY AIR
GIVING WAY TO RAPID SATURATION AND ACCUMULATING SNOW WITH
ENHANCEMENT NOTED IN REF DATA SHOWING SNOW RETURNS > 30 DBZ. THUS
EXPECT RAPID DETERIORATION THROUGH DAYBREAK IN BOTH VSBY AND CIG
HEIGHTS AS MOD-HVY SNOW BLOSSOMS FOR A TIME. PREDOMINATE IFR WITH
POCKETS OF LIFR THROUGH NOON INVOF KSBN AND THROUGH ABOUT 21Z INVOF
KFWA. OTHERWISE WINDS WILL GRADUALLY ESCALATE THROUGH THE DAY,
PEAKING LATE THIS AFTN AND EVENING WITH N-NERLY GUSTS AOA 30KTS AT
KFWA WHERE ISALLOBARIC PUSH IS LARGEST.
SOME UPTICKING IMPROVEMENT IN FLIGHT CONDITIONS EXPECTED OVERNIGHT
WITH MVFR AND DIMINISHING WINDS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WINTER STORM WARNING UNTIL 4 AM EST SUNDAY FOR INZ026-027-
032>034.
WINTER STORM WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR
INZ008-009-012>018-020-022>025.
WINTER STORM WARNING UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR INZ003>007.
MI...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MIZ077>081.
OH...WINTER STORM WARNING UNTIL 4 AM EST SUNDAY FOR OHZ016-024-025.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR OHZ001-002-
004-005-015.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST SUNDAY FOR LMZ043-046.
UPDATE...MARSILI
SYNOPSIS...MCD
SHORT TERM...MCD
LONG TERM...MCD
AVIATION...T
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