371
FXUS63 KIND 191622
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1115 AM EST SAT JAN 19 2019
UPDATE
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
SYNOPSIS
ISSUED AT 252 AM EST SAT JAN 19 2019
A STRONG LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS WILL SWEEP
ACROSS KENTUCKY TODAY AND REACH THE MIDDLE ATLANTIC STATES BY
SUNDAY. THE DEEP LOW WILL SPREAD A SWATH OF WINTER PRECIPITATION
ACROSS CENTRAL INDIANA. THE PRECIPITATION WILL START AS EITHER
RAIN...SNOW OR A MIX BEFORE CHANGING OVER TO ALL SNOW BY LATE
AFTERNOON ACROSS THE ENTIRE STATE. SIGNIFICANT SNOWFALL AMOUNTS
ARE EXPECTED RESULTING IN DIFFICULT TRAVEL CONDITIONS. GUSTY WINDS
MAY ALSO RESULT IN BLOWING AND DRIFTING SNOW.
ARCTIC HIGH PRESSURE WILL ARRIVE ACROSS THE AREA ON
SUNDAY...BRINGING SOME OF THE COLDEST TEMPERATURES INDIANA HAS
SEEN SO FAR THIS WINTER. THESE COLD TEMPERATURES WILL PERSIST
ACROSS INDIANA THROUGH MONDAY AS THE HIGH PRESSURE PASSES ACROSS
THE REGION.
RAIN AND WARMER TEMPERTURES ARE THEN EXPECTED TO ARRIVE ON TUESDAY
AS LOW PRESSURE MOVES THROUGH THE GREAT LAKES...DRAGGING A COLD
FRONT ACROSS INDIANA.
MORE COLD TEMPERATURES AND PRECIPITATION CHANCES ARE EXPECTED TO
RETURN NEXT WEEKEND.
NEAR TERM /TODAY/
ISSUED AT 950 AM EST SAT JAN 19 2019
AREAS NEAR A SOUTHWEST TO NORTHEAST CORRIDOR FROM NEAR TO FISHERS TO
NEAR KOKOMO HAVE SEEN SOME ICE ACCUMULATION WITH A FEW POWER OUTAGES
REPORTED. OTHERWISE, IT HAS BEEN MOSTLY RAIN SOUTH OF THI9S CORRIDOR
AND MOSTLY SNOW NORTH OF IT. THERE WAS A REPORT IN LAFAYETTE OF AN
INCH OF SNOW ACCUMULATION. THE PRECIPITATION SHOULD SWITCH TO JUST
SNOW FROM NORTHWEST TO SOUTHEAST THIS AFTERNOON AS THE COLD AIR
MOVES IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM. THE HIGHEST SNOW
ACCUMULATION IS EXPECTED NORTH OF INDIANAPOLIS AND ALSO SOUTHEAST OF
INDIANAPOLIS WITH LOWER AMOUNTS WEST CENTRAL.
PREVIOUS DISCUSSION FOLLOWS...
ISSUED AT 252 AM EST SAT JAN 19 2019
SURFACE ANALYSIS EARLY THIS MORNING SHOWS DEEP LOW PRESSURE IN
PLACE ACROSS NW ARKANSAS. A WARM FRONT EXTENDED NE FROM THE
LOW...INTO WESTERN KENTUCKY AND THEN ACROSS SOUTHERN KENTUCKY.
WATER VAPOR IMAGERY SHOWS A STREAM OF MOISTURE PUSH NORTHEAST
ACROSS TX AND INTO THE TENNESSEE VALLEY AHEAD OF A DEEP UPPER
TROUGH OVER OK AND KS. RADAR SHOWS A FEW ARES OF RAIN SHOWERS OVER
ILLINOIS PUSHING NE. EARLY RETURNS AT THE MOMENT IN INDIANA WERE
VIRGA. GFS AND NAM AGREE TO SWEEP THE SURFACE LOW ACROSS KENTUCKY
TODAY...AGAIN PLACING INDIANA WITHIN A FAVORABLE LOCATION FOR
SNOW AND PRECIP. 700MB LOW/TROUGH AXIS IS ALSO EXPECTED TO PUSH
ACROSS CENTRAL INDIANA LATE THIS AFTERNOON. BOTH OF THESE
FEATURES ARE FAVORABLE FOR SNOW...PARTICULARLY THE LATTER.
INITIALLY FORECAST SOUNDINGS HAVE TROUBLE FOR A WELL DESIGNED
FZRA SET-UP. TEMPS APPEAR EITHER TOO WARM AT THE SURFACE OR NOT
WARM ENOUGH ALOFT WHERE SURFACE TEMPS ARE EXPECTED TO BE COLDER. A
THIN AREA OF FREEZING PRECIP CANNOT BE RULED OUT BUT A SHARPER
RAIN/SNOW LINE APPEARS MORE LIKELY.
STRONG ISENTROPIC LIFT IS SEEN THIS MORNING AHEAD OF THE SYSTEM
ON THE GFS 290K SURFACE WITH SPECIFIC HUMIDITIES OVER 4 G/KG. THIS
LIFT IS LOST BY 18Z AND AFTER AS THE SURFACE LOW PASSES EAST AND
AND WRAP AROUND FLOW BECOMES MORE PREDOMINATE. AHEAD OF THE LOW
THIS MORNING...RAIN WILL BE THE PRIMARY PRECIP TYPE ALONG AND
SOUTH OF I-70 AS THE LOWER LEVEL LAYER LOOKS WARM ENOUGH TO MELT
PRECIP. FARTHER NORTH THE WARM LAYER IS MUCH SHALLOWER AND PRECIP
SHOULD FALL AS SNOW. THIS WILL BE THE INITIAL ROUND OF PRECIP
THIS MORNING...ASSOCIATED WITH THE WARM AIR ADVECTION ON THE FRONT
OF THE APPROACHING SYSTEM. THE SECOND ROUND OF OF SNOW LOOKS TO
COME THIS AFTERNOON AS THE MODELS AGAIN HINT AT A DEFORMATION BAND
SETTING UP ACROSS INDIANA THIS AFTERNOON AND EARLY EVENING. THIS
AREA APPEARS WHERE MORE OF OUR HEAVIER SNOW MIGHT COME
FRONT...PARTICULARLY ACROSS THE SOUTH AND EAST. AS THE LOW PASSES
THIS AFTERNOON...LOWER LEVEL FLOW BECOMES NORTHERLY AND FORECAST
SOUNDINGS SHOW ENOUGH COOLING THAT ALL PRECIP WILL FALL AS SNOW
ACROSS THE FORECAST AREA.
WHEN IT IS COMPLETED THIS EVENING...THESE TWO PUNCHES SHOULD
BRING 5-7 INCHES OF SNOW NORTH OF I-70 AND 4-6 AMOUNTS SOUTH AND
EAST OF INDIANAPOLIS. BLOWING AND DRIFTING MAY FURTHER COMPLICATE
DRIVING CONDITIONS. GIVEN THIS...OUR WARNING MAY NEED TO BE
EXPANDED TO THE SOUTHEAST.
FORECAST WISE 100 POPS ARE A SLAM DUNK AND WILL LOOK FOR STEADY
STATE TEMPS THIS MORNING AND FALLING TEMPS THIS AFTERNOON AMID
PRECIP AND COLD AIR ADVECTION.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/
ISSUED AT 252 AM EST SAT JAN 19 2019
GFS AND NAM CONTINUE TO SUGGEST EXTENSIVE MOISTURE AND LIFT ACRS
SOUTHEASTERN CENTRAL INDIANA NEAR 00Z AS SEEN IN THE MID LEVEL
DEFORMATION BAND. TEMPS AT THAT TIME CONTINUE TO SUPPORT
SNOW...ALTHOUGH THIS PRECIP SHOULD BE EXITING THE AREA QUICKLY
EAST BETWEEN 00Z AND 06Z. WILL CONTINUE TO USE HIGH POPS AT THAT
TIME TAPERING TO DRY OVERNIGHT AS FORCING DEPARTS TO THE EAST.
AGAIN...SNOW AMOUNTS WILL BE TRENDED UPWARD ACROSS THE SOUTHEAST
FOR THIS EVENING SNOWFALL SET-UP...AND SHOULD PROPEL THE
SOUTHEAST PARTS OF CENTRAL INDIANA INTO WARNING CRITERIA. STRONG
COLD AIR ADVECTION IS EXPECTED AS THE DEEP LOW DEPARTS. THIS
FEATURES WILL RESULT IN SOME GUSTY WINDS THIS AFTERNOON AND
EVENING...BLOWING AND DRIFTING SNOW MAY CONTINUE TO IMPACT TRAVEL.
GIVEN THE COLD AIR ADVECTION WILL TREND LOWS AT OR BELOW THE
FORECAST BUILDER BLENDS.
MODELS SUGGEST ARCTIC HIGH PRESSURE WILL SETTLE ACROSS THE OHIO
VALLEY ON SUNDAY IN THE WAKE OF THE DEPARTING LOW. STRONG RIDGING
ALOFT BEGINS TO DEVELOP OVER THE PLAINS STATES AND THIS FEATURE
PERSISTS UNTIL MONDAY NIGHT...KEEPING SUBSIDENCE IN PLACE ACROSS
INDIANA AND THE OHIO VALLEY. THUS WILL TREND TOWARD A DRY FORECAST
ON SUNDAY THROUGH MONDAY NIGHT...BUT WILL KEEP SOME CLOUD COVER
AROUND GIVEN THE COLD AIR ADVECTION. WILL TREND TEMPS AT OR BELOW
THE BLENDS.
LONG TERM /TUESDAY THROUGH SATURDAY/
ISSUED AT 325 AM EST SAT JAN 19 2019
THE LONG TERM PORTION OF THE FORECAST LOOKS TO BE SOMEWHAT ACTIVE
WITH ONE WELL ORGANIZED LOW PRESSURE SYSTEM IMPACTING THE AREA
EARLY IN THE PERIOD, AND THEN LINGERING CHANCES FOR LIGHT SNOW
FROM TIME TO TIME AS WEAKER UPPER LEVEL DISTURBANCES MOVE THROUGH
THE REGION IN THE LARGER SCALE CYCLONIC FLOW ALOFT. TEMPERATURES
EARLY IN THE PERIOD WILL RECOVER BRIEFLY FROM THE VERY COOL
READINGS DURING LATE WEEKEND INTO THE START OF THE WORK WEEK,
BEFORE ANOTHER SHOT OF ARCTIC AIR LATER IN THE WEEK REINFORCES THE
COLD AIR MASS IN PLACE ACROSS THE AREA.
BLENDED INITIALIZATION PERFORMED REASONABLY WELL AND REQUIRED ONLY
MINOR ADJUSTMENT.
AVIATION /DISCUSSION FOR 19/18Z TAF ISSUANCE/
ISSUED AT 1115 AM EST SAT JAN 19 2019
THE SREF AND GFS LAMP SUGGEST THE IFR AND WORST CONDITIONS IN RAIN
AND SNOW WILL IMPROVE TO MVFR AFTER 04Z AT IND AND BMG AFTER 04Z AT
IND AND BMG AND A FEW HOURS EARLIER AT THE OTHER SITES. HOWEVER,
THIS IS ONLY LOW TO MODERATE CONFIDENCE ON TIMING. THE SNOW SHOULD
END AFTER 00Z AT LAF AND SEVERAL HOURS LATER AT THE OTHER SITES.
IT WILL BE WINDY WITH NORTHEAST WINDS BECOMING NORTH AND GUSTS TO 30
KNOTS OR MORE THROUGH 06Z WITH SLIGHTLY LESSER GUSTS TO 10Z.
IND WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING UNTIL 4 AM EST SUNDAY FOR INZ021-028>031-
035>049-054>057-065.
WINTER WEATHER ADVISORY UNTIL 4 AM EST SUNDAY FOR INZ051>053.
WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST SUNDAY
FOR INZ062>064-067>072.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 4 AM EST
SUNDAY FOR INZ060-061.
SYNOPSIS...PUMA
NEAR TERM...PUMA/MK
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...MK
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