Area Forecast Discussion
Issued by NWS Indianapolis, IN

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385
FXUS63 KIND 120223
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
922 PM EST THU FEB 11 2016

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 330 PM EST THU FEB 11 2016

A COLD UPPER TROUGH OVER ONTARIO AND THE ST. LAWRENCE VALLEY WILL KEEP US
UNDER A NORTHWEST FLOW ALOFT AND TEMPERATURES COLDER THAN NORMAL THROUGH
EARLY NEXT WEEK.  A CLIPPER WILL GIVE US A CHANCE OF LIGHT SNOW TOWARDS
DAYBREAK OVER WESTERN SECTIONS AND MOST AREAS FRIDAY.  LAKE EFFECT
SNOW SHOWERS MAY LINGER TO MIDDAY SATURDAY ACROSS OUR NORTHEAST.

COLD HIGH PRESSURE WILL BUILD EAST ACROSS OUR REGION SATURDAY AND
SATURDAY NIGHT.  AN APPROACHING AREA OF LOW PRESSURE WILL SPREAD
SNOW ACROSS OUR REGION SUNDAY INTO MONDAY.   ANOTHER SYSTEM WILL
BRING A CHANCE OF SNOW MONDAY AND MONDAY NIGHT.  FINALLY A FOURTH
SYSTEM WILL BRING A CHANCE OF SNOW OR MIXED PRECIPITATION AROUND THE
MIDDLE OF NEXT WEEK.  TEMPERATURES WILL BEGIN TO MODERATE TOWARDS THE
MIDDLE OF NEXT WEEK AS OUR UPPER FLOW BECOMES MORE ZONAL.

&&

.NEAR TERM.../TONIGHT AND FRIDAY/
ISSUED AT 822 PM EST THU FEB 11 2016

GOING FORECAST IS IN EXCELLENT SHAPE. FLAKES MAY FLY ACROSS PORTIONS
OF CENTRAL INDIANA BY THE MORNING RUSH. FEEL CHANCE POPS HANDLE THIS
BEST HOWEVER AS THERE IS A LOT OF NEAR SURFACE DRY AIR TO OVERCOME.
WILL HAVE TO MONITOR FOR POSSIBLE IMPACTS TO FRIDAY MORNING COMMUTE
ACROSS THE AREA...ESPECIALLY AS HRRR AND NAM PROFILES INDICATE FIRST
FLAKES MAY BEGIN REACHING THE GROUND DURING THE HEART OF THE
COMMUTE. HOWEVER...RATES APPEAR UNLIKELY TO BE SUCH THAT RAPID
ACCUMULATION WOULD OCCUR...WHICH WOULD LIMIT POTENTIAL IMPACT.

PREVIOUS DISCUSSION FOLLOWS.

ISSUED AT 330 PM EST THU FEB 11 2016

HIGH PRESSURE CENTERED OVER ILLINOIS WILL MOVE EAST ACROSS INDIANA THIS
EVENING AND ON TO THE EAST BY MONDAY.   A WEAK CLIPPER OVER THE UPPER
MIDWEST AND NORTHERN PLAINS WILL MOVE TO THE MIDDLE MISSISSIPPI VALLEY
LATE TONIGHT AND ACROSS THE OHIO VALLEY FRIDAY.

MOSTLY CLEAR CONDITIONS WERE OCCURRING ACROSS WESTERN SECTIONS THIS AFTERNOON
WHILE PARTLY CLOUDY CONDITIONS WERE THE RULE IN THE EAST.   MID/HIGH CLOUDS
OVER THE MIDDLE MISSISSIPPI VALLEY WILL MOVE OUR WAY AND THICKEN OVERNIGHT.
ANY SNOW FROM THE CLIPPER PROBABLY WON`T REACH OUR AREA UNTIL AFTER 09Z AND
THIS WILL BE MAINLY ACROSS WESTERN AND SOUTHWEST AREAS.

SCATTERED LIGHT SNOW SHOWERS WILL SPREAD EAST ACROSS OUR REGION FRIDAY. AMOUNTS
WILL BE GENERALLY A QUARTER INCH. BUT SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE
ACROSS OUR NORTHEAST LATE FRIDAY AS OUR FLOW BECOMES MORE NORTHERLY AND AMOUNTS
THERE WILL BE A LITTLE HIGHER BY LATE FRIDAY.

LOWERED TEMPERATURES SLIGHTLY CENTRAL AND EAST TONIGHT AS HIGH PRESSURE WILL
PROVIDE GOOD RADIATIONAL COOLING EARLY ON.  OTHERWISE...A MOS BLEND OF TEMPERATURES
SEEM REASONABLE.   WINDS WILL BE LIGHT TONIGHT AND THEN BECOME NORTHWEST WITH
GUSTS UP TO 25 MPH BY FRIDAY AFTERNOON AS A PRESSURE GRADIENT STRENGTHENS.

&&

.SHORT TERM.../FRIDAY NIGHT THROUGH SUNDAY/
ISSUED AT 330 PM EST THU FEB 11 2016

WE WILL REMAIN UNDER A COLD NORTHWEST FLOW FRIDAY NIGHT SATURDAY AS HIGH
PRESSURE OVER THE NORTHERN PLAINS BUILDS OUR WAY.  MODELS INDICATE SOME FETCH OFF
OF LAKE MICHIGAN WHICH WILL PRODUCE SCATTERED LAKE EFFECT SNOW SHOWERS OVER
NORTHEAST SECTIONS.  WHILE COLD AND DRY WEATHER WILL BE THE RULE ELSEWHERE.

MODELS INDICATE 850 TEMPERATURES OF -15 TO -21 CELSIUS SATURDAY AND -8 TO -12
CELSIUS SUNDAY.  THIS WILL TRANSLATE TO HIGHS IN THE TEENS SATURDAY 20 TO 26
DEGREES SUNDAY.   LOWS WILL BE MOSTLY IN THE SINGLE DIGITS BOTH FRIDAY AND
SATURDAY NIGHT.  BUT LOWS NEAR ZERO ARE POSSIBLE SATURDAY NIGHT OVER NORTHEAST
SECTIONS AS CLOUDS MAY NOT ARRIVE THERE UNTIL LATE.

THE BIGGEST CONCERN WILL BE SNOW AMOUNTS SUNDAY AS AREA OF LOW PRESSURE MOVES
INTO THE UPPER MIDWEST AND A STRONGER CLIPPER MOVES OUR WAY.  THE NAM/OPERATIONAL
GFS AND THE NEW EURO ALL INDICATE AN INCH OR TWO OF SNOW BY SUNDAY AFTERNOON...
WHILE THE CANADIAN HARDLY HAS ANYTHING AS MOST OF ITS PRECIPITATION IS FARTHER
SOUTHWEST.  FOR NOW WILL GO WITH A BLEND.  WILL RAISE POPS TO LIKELY OVER WEST
CENTRAL AND NORTHWEST AND GO WITH HIGH CHANCE POPS ELSEWHERE BY SUNDAY AFTERNOON.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 237 PM EST FEB 11 2016

AN ACTIVE WEATHER PATTERN IS IN PLACE FOR THE LONG TERM. MODEL
VARIABILITY WITH THIS SYSTEM HAS BEEN AND CONTINUES TO BE FAIRLY
HIGH...AS DESCRIBED FURTHER BELOW. ESSENTIALLY AN UPPER WAVE WILL
MOVE SOMEWHERE THROUGH THE GREAT LAKES WITH AN ASSOCIATED SURFACE
SYSTEM SOMEWHERE TO ITS SOUTH AND THIS WILL BRING SNOW CHANCES TO
THE AREA. HOW MUCH SNOW AND WHERE IS STILL VERY MUCH IN QUESTION.

GFS ENSEMBLE MEMBERS ARE CLUSTERING MORE WITH THE HIGHER AMOUNTS
OVER NORTHERN INDIANA WITH A FEW MEMBERS PUTTING THE MAX ACROSS
THE CENTRAL PART OF THE STATE. 24 HOUR MAX AMOUNTS IN THE GEFS
VARY FROM 2 INCHES TO AROUND 6 INCHES. THE 12Z OPERATIONAL GFS HAS
A MAX OF AROUND 4+ INCHES ACROSS THE NORTHERN THIRD OF THE STATE
WITH 2-3 INCH AMOUNTS CENTRAL AND SHARPLY LESS SOUTH. THE 12Z
ECMWF THOUGH SHOWS SNOWFALL MAXES TO THE NORTH AND SOUTH WITH THE
IND CWA IN A LOCAL MINIMUM WITH AROUND 1-1.5 INCHES OR LESS. ECM
RUNS HAVE BEEN BOUNCING FROM A SOLUTION WITH A MAX WELL SOUTH OF
THE FORECAST AREA TO HIGHEST AMOUNTS ACROSS THE SOUTHERN COUNTIES.
0Z CANADIAN ENSEMBLE AVERAGE FAVORS THE SOLUTION THAT PUTS THE MAX
WELL SOUTH OF THE AREA. 0Z GFS CIPS ANALOGS SHOW THE HIGHEST
PROBABILITY FOR 2 INCHES OR GREATER IS ACROSS THE NORTHERNMOST
COUNTIES OF THE FORECAST AREA AND PROBABILITIES TAPER OFF HEADING
SOUTH.

FORECAST MODELS ARE FAIRLY CONSISTENT IN SHOWING DECENT
FORCING DURING THE SUNDAY NIGHT PERIOD SO WILL INCREASE POPS TO
LIKELY DURING THAT TIME. AT THIS MOMENT THOUGH WILL NOT CHANGE
SNOWFALL AMOUNTS FROM THOSE GIVEN BY THE BLENDED INITIALIZATION.
SNOW CHANCES STAY AROUND FOR MONDAY THROUGH TUESDAY IN CYCLONIC
FLOW. SHOULD SEE A SLOW WARMING TREND THROUGH THE WEEK WITH SMALL
CHANCES FOR RAIN OR SNOW TUESDAY AND WEDNESDAY.

&&

.AVIATION /DISCUSSION FOR THE 120300Z KIND TAF UPDATE/...
ISSUED AT 922 PM EST THU FEB 11 2016

NO CHANGES MADE TO THE FORECAST AT THIS TIME. PREVIOUS DISCUSSION
FOLLOWS.

EXPECTING CEILINGS TO GRADUALLY FALL TONIGHT OVER THE
TERMINALS...FALLING BELOW 050 DURING THE PRE DAWN HOURS OF FRIDAY AS
A DISTURBANCE APPROACHES FROM THE NORTHERN PLAINS. SOME LIGHT SNOW
MAY BEGIN AFFECTING THE TERMINALS AFTER ABOUT 120900Z. IFR VISIBILITY
RESTRICTIONS ARE POSSIBLE TOWARDS/AFTER SUNRISE ON FRIDAY AS THIS
DISTURBANCE MOVES THROUGH BASED ON OBSERVATIONS UPSTREAM. HOWEVER...THE
AREA OF BEST LIFT IS QUITE NARROW AND THERE ARE UNCERTAINTIES REGARDING
THE TRACK OF THE BEST LIFT. AS A RESULT...CONFIDENCE IN IFR RESTRICTIONS
AT ANY PARTICULAR TERMINAL IS LOW AT THIS TIME.

SURFACE WINDS UNDER 6 KTS TONIGHT.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...JH
NEAR TERM...JH/NIELD
SHORT TERM...JH
LONG TERM...CP
AVIATION...JAS



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