048
FXUS63 KIWX 261139
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
639 AM EST TUE JAN 26 2021
SYNOPSIS
ISSUED AT 527 AM EST TUE JAN 26 2021
A WINTRY MIX OF LIGHT SNOW AND FREEZING DRIZZLE OR DRIZZLE WILL
CONTINUE THROUGH THE EVENING. ROADS MAY BE SLICK FOR THE MORNING
COMMUTE. OTHERWISE, EXPECT MOSTLY CLOUDY SKIES WITH HIGHS IN THE
30S. MOSTLY DRY CONDITIONS ARE EXPECTED OVERNIGHT, WITH LOWS FALLING
INTO THE UPPER TEENS AND LOW TO MID 20S. LAKE EFFECT SNOW SHOWERS
ARE LIKELY NEAR LAKE MICHIGAN WEDNESDAY INTO THURSDAY, WITH PARTLY
TO MOSTLY CLOUDY SKIES EXPECTED ELSEWHERE. HIGHS WILL BE IN THE 20S
AND LOW 30S. LOWS WILL BE IN THE SINGLE DIGITS AND TEENS. DRY
CONDITIONS ARE EXPECTED FRIDAY.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 527 AM EST TUE JAN 26 2021
THE WINTER WEATHER ADVISORY REMAINS IN EFFECT THROUGH THIS
AFTERNOON. FORECAST LOOKS LARGELY ON TRACK. AREAS OF LIGHT FREEZING
DRIZZLE AND SNOW, OR DRIZZLE (FURTHER SOUTHEAST) WILL CONTINUE
THROUGH THE DAY FOR MOST AREAS, WITH CHANCES FOR MOSTLY SNOW
CONTINUING IN THE FAR NORTHWESTERN CWA WITH THE DEFORMATION ZONE OF
THE LOW PRESSURE SYSTEM MOVING IN. HAVE AN ADDITIONAL 1 TO 2 INCHES
FOR MAINLY SOUTHWEST LOWER MICHIGAN/FAR NW IN COUNTIES. AFTER THE
DRY SLOT EXITS THE AREA AND WE SEE A RETURN OF SOME OF THE DEEPER
MOISTURE/ICE IN THE CLOUD LATER THIS AFTERNOON WE WILL SEE A CHANGE
OVER BACK TO LIGHT SNOW. THE MORNING COMMUTE WILL BE HAZARDOUS THIS
MORNING GIVEN THE SNOW AND ICE ACCUMULATIONS WE HAD OVERNIGHT. THERE
IS A LITTLE BIT OF FOG (BR) AROUND, THOUGH THE DENSER FOG IS FURTHER
SOUTH OF OUR CWA, AND I'M UNCERTAIN AS TO WHETHER IT WILL MAKE IT
THIS FAR NORTH. MOST OF THE VISIBILITIES ARE CURRENTLY BETWEEN 2-5
MILES, SO OPTED TO LEAVE OUT OF THE FORECAST FOR NOW. HIGH
TEMPERATURES WILL LINGER AROUND FREEZING IN OUR NORTHWEST, AND
INCREASE INTO THE MID 30S GENERALLY SOUTH OF US 24. THIS WILL CAUSE
MORE OF A DRIZZLE (VS FREEZING DRIZZLE) BEFORE COLDER AIR SINKS
FURTHER SOUTHEASTWARD AND WE SEE SOME LIGHT SNOW SHOWERS INTO THE
EVENING.
WE'LL SEE A BREAK IN THE PRECIPITATION LATER TONIGHT INTO WEDNESDAY
MORNING BEFORE LAKE EFFECT SNOW CHANCES MOVE IN. WINDS WILL REMAIN
OUT OF THE NORTHEAST THROUGH THE NIGHT, WHICH SHOULD PRECLUDE ANY
LAKE EFFECT THAT DEVELOPS OVER CHICAGO'S AREA FROM SHIFTING INTO OUR
NORTHWESTERN COUNTIES. EXPECT MOSTLY CLOUDY SKIES OVERNIGHT WITH
LOWS FALLING INTO THE TEENS AND LOW TO MID 20S.
LONG TERM
(WEDNESDAY THROUGH MONDAY)
ISSUED AT 527 AM EST TUE JAN 26 2021
WEDNESDAY INTO THURSDAY WE'LL SEE MOSTLY DRY CONDITIONS BEYOND SOME
LAKE EFFECT. NORTHEASTERLY WINDS WILL GRADUALLY SHIFT MORE NORTHERLY
BY WEDNESDAY AFTERNOON BEHIND AN UPPER LEVEL TROUGH, WHICH WILL
REORIENT THE LAKE ENHANCED SNOW BAND OVER CHICAGO TO BE MORE NORTH-
SOUTH (VS SW TO NE) AND SHIFT IT INTO OUR AREA. GIVEN THE LONG FETCH
ACROSS LAKE MI, INVERSION HEIGHTS AROUND 5-6KFT, THE UPPER LEVEL
WAVE MOVING THROUGH, AND DECENT DELTA THETA-E VALUES THROUGH EARLY
THURSDAY I OPTED TO INCREASE POPS TO LIKELY OR HIGH CHANCE. HIGH
PRESSURE WILL BUILD IN FROM THE WEST BY THURSDAY AFTERNOON, BRINGING
IN DRIER AIR AND LOWER INVERSION HEIGHTS. WINDS WILL ALSO GRADUALLY
SHIFT TO THE WEST, BLOWING THE BAND FURTHER INLAND TO THE EAST
BEFORE IT DISSIPATES ALTOGETHER. EXPECT AROUND 1 TO 2 INCHES OF SNOW
NEAR LAKE MICHIGAN, WITH TRACE AMOUNTS ELSEWHERE FROM WEDNESDAY INTO
THURSDAY. IT WILL BE COLDER, WITH HIGH TEMPERATURES IN THE 20S AND
LOW 30S. LOWS WILL BE IN THE SINGLE DIGITS AND TEENS.
AS FOR ANY SYNOPTIC SNOW WITH THE UPPER LEVEL TROUGH WEDNESDAY,
OPTED TO KEEP ONLY SLIGHT CHANCES FOR SNOW IN THE FAR SOUTH. MOST OF
THE GUIDANCE KEEPS DEVELOPING PRECIPITATION WELL SOUTH OF US, BUT
THE ECMWF (AND THE NAM) STILL GRAZES OUR BORDER WITH LIGHT QPF
DURING THE AFTERNOON HOURS (MOVING WEST TO EAST). CONFIDENCE IS NOT
HIGH IN THIS OCCURRING.
THURSDAY NIGHT INTO SATURDAY MORNING HIGH PRESSURE BUILDS IN
OVERHEAD, BRINGING DRY CONDITIONS AND PARTLY TO MOSTLY SUNNY SKIES.
HIGHS FRIDAY WILL BE IN THE MID-UPPER 20S AND LOW TO MID 30S
(WARMEST FAR SOUTHWEST). LOWS WILL BE IN THE TEENS AND 20S.
FOR THE WEEKEND AND START OF NEXT WEEK, THE UPPER LEVEL RIDGE WILL
AMPLIFY IN RESPONSE TO A DIGGING TROUGH (OR CLOSED LOW) DIVING INTO
THE CENTRAL PLAINS. KEPT CONSENSUS POPS (LIKELY TO CHANCE) SATURDAY
INTO MONDAY AS THE SURFACE LOW ASSOCIATED WITH THE UPPER LEVEL
TROUGH SHIFTS EAST-NORTHEAST FROM MO INTO NORTHERN IN/OH. THERE ARE
SIGNIFICANT TIMING AND EVOLUTION DIFFERENCES BETWEEN MODELS AT THIS
POINT, BUT HAVE CHANCES FOR RAIN AND SNOW THROUGH THE PERIOD,
HIGHEST ON SATURDAY AHEAD OF THE WARM FRONT AND THEN AGAIN ON THE
BACKSIDE OF THE LOW FOR SUNDAY INTO MONDAY (MONDAY IS SLIGHT
CHANCES). IT WILL BE SLIGHTLY WARMER, WITH HIGHS IN THE LOW TO MID
30S NORTH AND CENTRAL, AND MID TO UPPER 30S SOUTH.
ANOTHER UPPER LEVEL RIDGE/SURFACE HIGH BUILDS IN BEHIND THE SYSTEM
FOR MONDAY NIGHT INTO TUESDAY, BRINGING A RETURN TO DRY
CONDITIONS.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 639 AM EST TUE JAN 26 2021
IFR/LIFR CONDITIONS WILL PERSIST THROUGH MUCH OF TODAY WITH
MOISTURE-LADEN LOW LEVEL TROUGH REMAINING OVER THE AREA UNTIL LATE
EVENING. VERY LIGHT FREEZING DRIZZLE WILL CONTINUE THROUGH THE
MORNING (MIXING WITH SNOW AT KSBN) BUT VERY LITTLE ADDITIONAL
ACCUMULATION IS EXPECTED BEFORE PRECIP TAPERS OFF DURING THE LATE
AFTERNOON. SOME POTENTIAL FOR VISIBILITIES TO DROP BELOW 1SM AT
KFWA LATER THIS MORNING BUT CONFIDENCE IS NOT HIGH AND IMPACTS
WILL BE LARGELY DRIVEN BY VERY LOW STRATUS ANYWAY (POTENTIALLY
DROPPING TO 300 FT FOR A TIME THIS MORNING). SLOW IMPROVEMENT
ANTICIPATED INTO THE EVENING AS TROUGH EXITS AND DRIER AIR BEGINS
TO FILTER SOUTH. MAY RETURN TO VFR BY 09Z WEDNESDAY (PARTICULARLY
AT KSBN) BUT WILL HOLD OFF ONE MORE CYCLE BEFORE ADDING THAT
TRANSITION.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR INZ003>009-012>018-020-022>027-032>034.
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ077>081.
OH...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR OHZ001-
002-004-005-015-016-024-025.
LM...SMALL CRAFT ADVISORY UNTIL 10 AM EST THURSDAY FOR LMZ043-046.
SYNOPSIS...MCD
SHORT TERM...MCD
LONG TERM...MCD
AVIATION...AGD
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