Ice storm warning for Indy
Posted by JAC on 2/1/2011, 2:33 pm




MESOSCALE DISCUSSION 0068
  NWS STORM PREDICTION CENTER NORMAN OK
  1142 AM CST TUE FEB 01 2011
 
  AREAS AFFECTED...PORTIONS OF SRN/E-CNTRL MO...CNTRL IL...CNTRL IND
 
  CONCERNING...WINTER MIXED PRECIPITATION
 
  VALID 011742Z - 012245Z
 
  MODERATE TO HEAVY MIXED PRECIPITATION WILL EXPAND EWD ACROSS
  PORTIONS OF THE LOWER GREAT LAKES AND OHIO VALLEY REGION THROUGH
  22Z. SIGNIFICANT ICING...WITH FREEZING RAIN RATES AOA 0.25 INCH PER
  3 HOURS...WILL BE A CONCERN IN THE SRN HALF OF THE DISCUSSION
  AREA...WITH SLEET EXPECTED FURTHER NORTH.
 
  A POWERFUL EXTRATROPICAL CYCLONE CONTINUES TO MATURE OVER THE CNTRL
  CONUS...WITH A WELL-DEFINED/INTENSE WARM CONVEYOR BELT IN THE ERN
  SEMICIRCLE OF THE CYCLONE. THE 15Z RUN OF THE RUC INDICATES A SLY
  850-MB JET MAX WITH CORE WINDS OF 70 KT OVER PORTIONS OF THE LOWER
  OH VALLEY AND MID-SOUTH. THIS IS SUPPORTING STRONG NWD TRANSPORT OF
  DEEP-LAYER MOISTURE...WITH AMSU/SSMI TOTAL PRECIPITABLE WATER
  PRODUCT INDICATING AN INFLUX OF PWAT VALUES AROUND 1.5 INCHES NOSING
  INTO THE LOWER MS VALLEY REGION. DEEP-LAYER ASCENT ASSOCIATED WITH
  THE WARM CONVEYOR BELT RISING ATOP THE COLD AIR MASS ENTRENCHED
  ACROSS THE OHIO VALLEY REGION WILL BE AUGMENTED BY INTENSE
  UPPER-LEVEL DIVERGENCE EXPECTED TO RESULT FROM A COUPLED JET STREAK
  STRUCTURE LATER THIS AFTERNOON. AS PRECIPITATION FALLS INTO A
  NEAR-SURFACE SUB-FREEZING LAYER AT LEAST 60 STATUTE MILES NORTH OF
  THE OH RIVER...MIXED PRECIPITATION TYPES ARE EXPECTED THIS
  AFTERNOON.
 
  ACROSS THE SRN HALF OF THE DISCUSSION AREA WHERE LOW-LEVEL WARMING
  WILL BE STRONGEST...TEMPERATURES AOA 3C IN THE ELEVATED WARM LAYER
  WILL SUPPORT COMPLETE MELTING OF HYDROMETEORS. FREEZING RAIN IS
  ANTICIPATED IN THIS REGION...AS THE PRECIPITATION INTERACTS WITH
  SUB-FREEZING SFC TEMPS. HEAVY FREEZING RAIN WILL BE POSSIBLE...AS
  THE 12Z NAM MODEL INDICATES UPRIGHT INSTABILITY ENTERING THE REGION
  IN ASSOCIATION WITH THE WARM CONVEYOR BELT. THE ASSOCIATED
  CONVECTIVE ENHANCEMENT...POTENTIALLY ACCOMPANIED BY LIGHTNING...WILL
  ALLOW LIQUID-EQUIVALENT TO EXCEED 0.25 INCH PER 3 HOURS PER THE HRRR
  MODEL. THIS WILL LIKELY RESULT IN SIGNIFICANT ICING.
 
  ACROSS THE NRN HALF OF THE DISCUSSION AREA...TEMPERATURES IN THE
  ELEVATED WARM LAYER ARE EXPECTED TO REMAIN BELOW 3C...ALLOWING ONLY
  PARTIAL HYDROMETEOR MELTING...WITH MAINLY SLEET EXPECTED. THE NAM
  MODEL INDICATES SLANTWISE INSTABILITY SPREADING E/NEWD ACROSS THIS
  REGION...SUGGESTING THE POTENTIAL FOR MESOSCALE BANDING AND LOCALLY
  HEAVY SLEET RATES.
 
  ..COHEN/ROGERS.. 02/01/2011



URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
136 PM EST TUE FEB 1 2011

...POTENTIALLY CATASTROPHIC WINTER STORM TO CONTINUE TO IMPACT
CENTRAL INDIANA...

.A STRONG LOW PRESSURE SYSTEM OVER CENTRAL TEXAS WILL MOVE ACROSS
CENTRAL INDIANA TONIGHT AND WEDNESDAY. THIS SYSTEM IS EXPECTED TO
PRODUCE LARGE AMOUNTS OF SNOW ACROSS NORTHWESTERN PARTS OF
CENTRAL INDIANA AND LARGE ICE AMOUNTS ELSEWHERE. MANY AREAS ALONG
INTERSTATE 70 SAW A TENTH TO A QUARTER INCH OR MORE OF ICE LAST
NIGHT AND EARLY THIS MORNING ALONG WITH PERIODS OF SLEET.
MEANWHILE...AREAS NEAR LAFAYETTE SAW OVER AN INCH OF SNOW ALONG
WITH ADDITIONAL SLEET ACCUMULATION.

A BRIEF LULL IN THE ACCUMULATING PRECIPITATION WILL COME TO AN
END AS FREEZING RAIN...SLEET...AND SNOW WILL BEGIN ACROSS THE
AREA THIS AFTERNOON AS THE STRONG LOW PRESSURE SYSTEM SWINGS OUT
OF THE SOUTHERN PLAINS. COLD AIR WILL CONTINUE TO BE IN PLACE AT
THE SURFACE...HOWEVER VERY WARM AND MOIST AIR WILL BE PULLED INTO
THE SYSTEM ON SOUTHERLY WINDS...RESULTING IN WARM AIR ALOFT. THIS
WILL RESULT IN FREEZING RAIN OR SLEET ACROSS MUCH OF CENTRAL
INDIANA THROUGH TUESDAY NIGHT. AS THE LOW PASSES MOVES THROUGH
THE AREA AND OFF TO THE EAST WEDNESDAY MORNING... ALL OF THE
PRECIPITATION WILL CHANGE OVER TO SNOW.

AT THIS TIME...NORTH AND NORTHWEST CENTRAL INDIANA...INCLUDING
THE CITIES OF DELPHI AND LAFAYETTE...LOOK TO REMAIN COLD ENOUGH
THAT A SIGNIFICANT PORTION OF THE PRECIPITATION MAY FALL IN THE
FORM OF SNOW. SNOWFALL MAY BE HEAVY AND AMOUNTS IN EXCESS OF 12
INCHES ARE POSSIBLE BY WEDNESDAY EVENING.

FARTHER SOUTH...INCLUDING THE CITIES OF TERRE HAUTE...
INDIANAPOLIS...BLOOMINGTON...NEW CASTLE AND MUNCIE...WARM AIR IS
EXPECTED TO BE PRESENT AND PRECIPITATION SHOULD CONTINUE TO FALL
AS FREEZING RAIN AND SLEET. SIGNIFICANT ICE ACCUMULATION IS
POSSIBLE...WITH ICE ACCUMULATION OF ONE INCH OR MORE.
FURTHERMORE...STRONG WINDS GUSTING UP TO 40 MPH ARE EXPECTED FROM
LATE TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON. THIS
COMBINATION WILL RESULT IN WIDESPREAD DOWNED TREES AND POWER
LINES.

A LARGE AREA OF CENTRAL INDIANA MAY RECEIVE LARGE ICE
ACCUMULATIONS AND STRONG WINDS BY WEDNESDAY AFTERNOON. THIS WILL
RESULT IN WIDESPREAD TREES DOWN AND WIDESPREAD POWER OUTAGES.
LONG DURATION POWER OUTAGES WILL BE LIKELY FOR MANY PEOPLE IN
CENTRAL INDIANA.

INZ030-031-036>049-051>057-060>065-020245-
/O.CON.KIND.IS.W.0001.000000T0000Z-110202T1200Z/
/O.CON.KIND.WS.W.0002.110202T1200Z-110203T0000Z/
CLINTON-HOWARD-MONTGOMERY-BOONE-TIPTON-HAMILTON-MADISON-DELAWARE-
RANDOLPH-VERMILLION-PARKE-PUTNAM-HENDRICKS-MARION-HANCOCK-HENRY-
VIGO-CLAY-OWEN-MORGAN-JOHNSON-SHELBY-RUSH-SULLIVAN-GREENE-MONROE-
BROWN-BARTHOLOMEW-DECATUR-
INCLUDING THE CITIES OF...FRANKFORT...KOKOMO...CRAWFORDSVILLE...
ANDERSON...MUNCIE...INDIANAPOLIS...TERRE HAUTE...SHELBYVILLE...
BLOOMINGTON...COLUMBUS
136 PM EST TUE FEB 1 2011

...ICE STORM WARNING REMAINS IN EFFECT UNTIL 7 AM EST WEDNESDAY...
...WINTER STORM WARNING REMAINS IN EFFECT FROM 7 AM TO 7 PM EST
WEDNESDAY...

AN ICE STORM WARNING REMAINS IN EFFECT UNTIL 7 AM EST WEDNESDAY.
A WINTER STORM WARNING REMAINS IN EFFECT FROM 7 AM TO 7 PM EST
WEDNESDAY.

* MAIN IMPACT: ROADS WILL LIKELY BECOME IMPASSABLE DUE TO
SIGNIFICANT ICING...TRAVEL WILL BECOME VERY HAZARDOUS OR
POTENTIALLY IMPOSSIBLE TONIGHT AND WEDNESDAY. ICE ACCUMULATIONS
MAY RESULT IN WIDESPREAD...LONG DURATION POWER OUTAGES.

* ACCUMULATIONS: ICE ACCUMULATIONS OF A HALF INCH TO ONE INCH ARE
EXPECTED...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ALONG AND NEAR
THE INTERSTATE 70 CORRIDOR.

* TIMING: PRECIPITATION WILL BEGIN AGAIN BETWEEN 2 AND 4 PM THIS
AFTERNOON AND INCREASE IN INTENSITY THIS EVENING.

* OTHER IMPACTS: WIND GUSTS OF 35 TO 40 MPH LATER THIS AFTERNOON
AND TONIGHT INTO WEDNESDAY IN COMBINATION WITH HEAVY ICE
ACCUMULATIONS WILL LIKELY RESULT IN DOWNED TREES AND POWER
LINES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW...
SLEET...AND ICE ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO
POSSIBLE. THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

AN ICE STORM WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF ICE ACCUMULATIONS
WILL MAKE TRAVEL DANGEROUS OR IMPOSSIBLE. TRAVEL IS STRONGLY
DISCOURAGED. COMMERCE WILL LIKELY BE SEVERELY IMPACTED. IF YOU
MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...FOOD...AND WATER IN YOUR
VEHICLE IN CASE OF AN EMERGENCY. ICE ACCUMULATIONS AND WINDS WILL
LIKELY LEAD TO SNAPPED POWER LINES AND FALLING TREE BRANCHES THAT
ADD TO THE DANGER.

&&

$$
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Megastorm cranking up - JAC, 2/1/2011, 8:14 am
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