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000
FXUS63 KIND 100449
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1149 PM EST TUE FEB 9 2010

.AVIATION...DISCUSSION FOR 6Z TAFS.
MOSTLY IFR ACROSS THE SITES FROM VISIBILITIES DUE TO SNOW AND
BLOWING SNOW. COULD SEE THE INTENSITY OF THE SNOWFALL INCREASE OVER
THE NEXT FEW HOURS AS AN UPPER DISTURBANCE MAKES ITS WAY ACROSS
CENTRAL INDIANA SO WILL KEEP IFR GOING DURING THIS TIME. WINDS WILL
PICK UP TO GUSTS AOA 30 KTS IN THE 10-12Z TIMEFRAME AND THE
GUSTINESS SHOULD CONTINUE THROUGH AT LEAST MIDDAY. THIS WILL
CONTINUE TO CAUSE SOME VISIBILITY PROBLEMS BUT HAVE BACKED THEM OFF
TO MVFR ONCE SNOWFALL STOPS AFTER 12Z.

&&

.UPDATE...HAD TO UPDATE DO TO TEMPERATURES FALLING BELOW FORECASTED
NUMBERS. LOOKING UPSTREAM ACROSS ILLINOIS HOWEVER...LOOKS LIKE
TEMPERATURES WILL BOUNCE BACK UP INTO THE UPPER TEENS OVERNIGHT...SO
HAVE RISING OVERNIGHT TEMPERATURES IN THE ZONES. MEANWHILE...RAPID
REFRESH...RADAR TRENDS AND WEAK INTENSITY OF THE SNOW FAVOR KEEPING
SMALL ACCUMULATION AMOUNTS IN OVERNIGHT WITH HIGHEST POTENTIAL
CONTINUING TO BE ACROSS NORTHEASTERN COUNTIES. BLOWING AND DRIFTING
WILL BE A PROBLEM ESPECIALLY AFTER 06Z BASED ON UPSTREAM OBS AND
BUFKIT. BUFKIT CONTINUES TO SHOW THE POTENTIAL OF AT LEAST 35 MPH
GUSTS OVERNIGHT AND WEDNESDAY

&&

.SHORT TERM.../TONIGHT THROUGH FRIDAY/

FORECAST FOCUS CONTINUES TO BE ON COMPLEX WINTER STORM.

AT 19Z SURFACE LOW PRESSURE WAS ACROSS WESTERN OHIO AND EASTERN
KENTUCKY. A STRONG UPPER LOW WAS ACROSS MISSOURI. SNOW HAD
DIMINISHED ACROSS THE FORECAST AREA WITH THE DRY SLOT OVERHEAD.

MODELS ARE IN DECENT AGREEMENT...SO WILL USE A BLEND.

TONIGHT THE UPPER LOW WILL MOVE ACROSS THE AREA. ONE AREA OF LIGHT
SNOW CURRENTLY AHEAD OF THE UPPER LOW ACROSS ILLINOIS WILL MOVE INTO
MAINLY THE NORTHERN TWO THIRDS OF THE FORECAST AREA LATE THIS
AFTERNOON AND EARLY THIS EVENING. AFTER THE UPPER LOW PASSES...A
TROWAL WILL IMPACT MAINLY THE NORTHERN HALF OF THE AREA OVERNIGHT.
THUS STILL EXPECT ADDITIONAL MEASURABLE SNOW TONIGHT. LOOKS LIKE
ANOTHER 1 INCH ACROSS THE AREA WITH PERHAPS ANOTHER 2-3 INCHES
ACROSS THE FAR NORTH DEPENDING ON HOW WELL THE TROWAL PERFORMS. THIS
SYSTEM HAS BEHAVED WITH A MIND OF ITS OWN...SO CONFIDENCE IS NOT
HIGH ON THESE SNOW AMOUNTS. DURING THE EVENING WINDS WILL GUST OVER
20KT BUT THEN OVERNIGHT WINDS WILL START GUSTING OVER
30KT...ESPECIALLY LATE TONIGHT AS WINDS NOT TOO FAR OFF THE SURFACE
/925MB/ REACH 40-50KT. THIS SHOULD CAUSE CONSIDERABLE BLOWING AND
DRIFTING OF SNOW...EVEN THOUGH ACTUAL SNOW ON THE GROUND MAY NOT BE
TOO HIGH AT SOME LOCATIONS IN THE FORECAST AREA.

ON WEDNESDAY THE GUSTY WINDS AND BLOWING/DRIFTING SNOW WILL CONTINUE
ESPECIALLY DURING THE MORNING. THERE WILL ALSO BE SOME LIGHT
SNOW...ESPECIALLY ACROSS THE EASTERN AREAS AS THE SYSTEM PULLS AWAY.
THE MORNING COMMUTE COULD BE ROUGH AGAIN DUE TO THE BLOWING
SNOW...ESPECIALLY FOR THOSE THAT COMMUTE FROM RURAL AREAS. GIVEN ALL
THE ABOVE...FEEL THAT THE WINTER STORM WARNING/WINTER WEATHER
ADVISORY STILL LOOKS GOOD GIVEN THE POTENTIAL IMPACTS OF THE
WEATHER...EVEN IF WE DON/T GET WINTER STORM SNOWFALL CRITERIA. THUS
WILL MAKE NO CHANGES TO THE WARNING/ADVISORY. /INTERESTING
NOTE...SKIES MAY ACTUALLY CLEAR FOR A BRIEF PERIOD THIS EVENING
ACROSS THE SOUTHERN FORECAST AREA AHEAD OF THE UPPER LOW WHICH MAY
CAUSE SOME CONCERN WITH A WARNING IN EFFECT...BUT THIS WILL ONLY BE
BRIEF AND CONDITIONS WILL DETERIORATE ONCE AGAIN AS NOTED ABOVE./

CONCERNING TEMPERATURES...VERY INTERESTING PATTERN TONIGHT AS THE
MUCH COLDER AIR IS BENEATH THE UPPER LOW. THIS COLD AIR WILL MOVE
ACROSS THE AREA DURING THE FIRST HALF OF THE NIGHT...AND THIS IS
WHEN THE LOW TEMPERATURE WILL OCCUR. TEMPERATURES SHOULD RISE
OVERNIGHT BACK TO AROUND 20 DEGREES. MOS DOES NOT CAPTURE THIS SO
WENT CLOSE TO THE NAM SURFACE TEMPERATURE FORECAST TONIGHT. FOR
WEDNESDAY UNDERCUT MOS ONCE AGAIN...THIS TIME DUE TO EFFECTS OF SNOW
COVER.

PRECIPITATION MIGHT LINGER IN THE FAR EAST WEDNESDAY EVENING...THEN
DRY AND COOL WEATHER EXPECTED THROUGH FRIDAY. WILL CONTINUE TO CUT
MOS FOR HIGHS WITH THE FRESH SNOW COVER.

&&

.LONG TERM.../FRIDAY NIGHT THROUGH TUESDAY/

FAIRLY SIGNIFICANT DIFFERENCES BETWEEN ECM AND GFS. GEM MORE OR LESS
IN THE MIDDLE. HPC DISCUSSIONS AND FORECASTS ALSO SEEM TO BE LEANING
TOWARD MIDDLE OF WAY BETWEEN ECM AND GFS. LOOKS REASONABLE.

IN PRACTICAL TERMS THIS MEANS SLIGHT CHANCE TO CHANCE OF SNOW FRIDAY
NIGHT INTO SUNDAY AS WEAK LOWS PASS. WILL PROBABLY BE ABLE TO
ELIMINATE POPS SOME OF THESE PERIODS LATER AS BETTER RESOLUTION
BECOMES POSSIBLE. SNOW SHOWERS MAY CONTINUE MAINLY EAST SUNDAY NIGHT
AS COLD ADVECTION GETS UNDERWAY...THEN DRY.

HPC TEMPERATURES LOOK PRETTY GOOD FROM THICKNESS AND 850
TEMPERATURES...BUT WILL CUT HIGHS SLIGHTLY TO ALLOW FOR INCREASING
SNOW DEPTH TODAY AND TONIGHT THAT GUIDANCE CAN NOT KNOW ABOUT.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR INZ021-028>031-
035>049-054>057-062>065-070>072.

WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR INZ051>053-
060-061-067>069.

&&

$$

UPDATE...MK
AVIATION...CP
SHORT TERM...50
LONG TERM...KWIATKOWSKI