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000
FXUS63 KIWX 162132 CCA
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
520 PM EDT SUN JUN 16 2013

.SYNOPSIS...
ISSUED AT 519 PM EDT SUN JUN 16 2013

A FEW SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS THE
SOUTHERN PORTION OF THE AREA THIS EVENING. SKIES WILL THEN BECOME
PARTLY CLOUDY TO MOSTLY CLEAR TONIGHT WITH LOWS DROPPING INTO THE
UPPER 50S AND LOW 60S. MONDAY WILL START OFF DRY BEFORE A CHANCE
OF SHOWERS AND THUNDERSTORMS RETURNS TO THE AREA DURING THE
EVENING AND INTO THE OVERNIGHT HOURS. HIGH TEMPERATURES ON MONDAY
ARE EXPECTED TO BE IN THE LOW TO MID 80S.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 453 PM EDT SUN JUN 16 2013

BROAD TROF OVER CANADA AS THE LOW OVER SASKATCHEWAN OPENS AND BEGINS
TO INJECT INTO THE WESTERLIES. OF NOTE ALSO THE COASTAL RIDGE INTO
ALASKA WITH CLOSED/CUTOFF LOW OFF THE PACIFIC NORTHWEST. THIS BLOCK
HAS KEPT THE WESTERLIES ACTIVE ACROSS THE NORTHERN PLAINS AND WITH
THE RIDGE OVER THE SOUTH/CENTRAL PLAINS...CONVECTION HAS BEEN ABLE
TO DEVELOP WITH EACH WAVE.

AFTER THE LATEST ROUND OF PRECIPITATION MOVED OUT OF THE FORECAST
AREA...COOLER SURFACE HIGH PRESSURE HAS SETTLED FROM IOWA TO
KENTUCKY. AFTER MIXING OUT THE INVERSION/CAP THIS MORNING CONVECTIVE
TEMPERATURES WERE REACHED AND HAVE SEEN A BROAD AREA OF COLD POOL CU
OVERSPREAD THE REGION. INSTABILITY IS LACKING AND SOUNDINGS SUPPORT
SC/CU WITH VERY LITTLE CHANCE OF ANY SIGNIFICANT PRECIPITATION.

SURFACE FRONT/DEFORMATION AXIS EXTENDS FROM NORTHERN MICHIGAN TO
NEAR KANSAS CITY AND THIS WILL BE SLOWLY PUSHED SOUTH AND EAST
DURING THE OVERNIGHT. PREVIOUS MODEL RUNS HAD BEEN BRINGING ANOTHER
ROUND OF CONVECTION INTO THE GREAT LAKES REGION DURING THE DAY
MONDAY...HOWEVER LATEST RUNS OF THE SHORT RANGE AND HIGHER
RESOLUTION MODELS SHOW BEST INSTABILITY AND SYNOPTIC FORCING TO BE
FURTHER WEST AND EXTENDING SOUTH INTO KY/TN DURING THE DAY MONDAY.

THUS HAVE TAKEN PRECIP AND WEATHER OUT OF THE FORECAST FOR THE DAY
MONDAY. THERE COULD BE ISOLATED SHOWERS ALONG THE DEFORMATION AXIS
LATE IN THE DAY. HAVE NOT CHANGED TEMPS FOR TONIGHT OR MONDAY.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 453 PM EDT SUN JUN 16 2013

THE TIMING OF SHORT WAVE ENERGY IN THE FORM OF A WEAK UPPER LEVEL
TROF EJECTING OUT OF THE NRN PLAINS INTO SOUTH CENTRAL CANADA WAS
VERY CHALLENGING AT THE ONSET OF THE LONG TERM PERIOD. NCEP AND
OTHER MODELS WERE HAVING GREAT DIFFICULTY RESOLVING THE CORRECT
SOLUTION FOR THIS WEAK SYSTEM. THE ECMWF HAS A MASSIVE 15 STANDARD
DEVIATIONS AMONG ENSEMBLE MEMBERS CONCERNING THE 12 HOUR RAIN
CHANCES BOTH MONDAY NIGHT AND TUESDAY. THE GFS SPREAD WAS A LITTLE
MORE SUBDUED...BUT WAS STILL REFLECTING UNUSUALLY LARGE STANDARD
DEVIATIONS AMONG ENSEMBLE MEMBERS. FOR NOW...KEPT LOW CHANCES FOR
SHOWERS AND STORMS MONDAY NIGHT...THEN DRY TUESDAY GIVEN THIS
UNCERTAINTY. ANY STORMS EARLY IN THE PERIOD ARE NOT EXPECTED TO
BECOME SEVERE GIVEN LIMITED BULK SHEAR AND CAPE. OTHERWISE...
PREFERRED THE ECMWF LATE IN THE PERIOD WHICH HAS SHOWN A GRADUAL RUN
TO RUN TREND OF BUILDING THE UPPER LEVEL RIDGE GRADUALLY NORTH AND
NORTH EAST. THE FORECAST CONTINUES VERY CHALLENGING GIVEN THE
LIKELIHOOD OF WEAK SHORT WAVE TROFS TOPPING THE UPPER RIDGE AND
MOVING INTO THE GREAT LAKES REGION. ALSO CONCERN FOR AN ELEVATED
MIXED LAYER THAT WOULD ENHANCE THE CHANCE FOR STORMS AND RAISE THE
POSSIBILITY FOR SEVERE STORMS THIS WEEKEND. THE CAVEAT IS HOW STRONG
WILL THE CAP BE THIS COMING WEEKEND...AND IF THE CAP WILL BE ABLE TO
PREVENT CONVECTION AS 850 TEMPS CLIMB TO 20C. FOR NOW...GIVEN THIS
UNCERTAINTY....LEFT SATURDAY DRY...FOLLOWED BY A CHANCE FOR SHOWERS
AND STORMS SATURDAY NIGHT AND SUNDAY. HOWEVER...THERE IS STILL VERY
MUCH UNCERTAINTY IN THE FORECAST FOR NEXT WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 453 PM EDT SUN JUN 16 2013

HIGH PRESSURE EXTENDS FROM SOUTHERN IOWA INTO KENTUCKY. WESTERLY
FLOW CONTINUES ACROSS THE NORTHERN PLAINS INTO THE GREAT LAKES
WITH EMBEDDED SHORTWAVES AND SURFACE TROFS. SURFACE
FRONT/DEFORMATION AXIS EXTENDS FROM NRN MI-ACROSS LAKE MI TO NEAR
KANSAS CITY. THIS BOUNDARY WILL GRADUALLY SHIFT EAST AND SOUTHEAST
THROUGH THE FORECAST PERIOD. WITH POOL OF COOLER AIR OVER THE
REGION...CU/SC HAVE FORMED AND EXPECT TO SEE CLEARING SKIES AFTER
SUNSET. VERY LIGHT AND ISOLD SHRA ARE POSSIBLE...HOWEVER NOT
EXPECTED TO IMPACT TERMINALS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...KG
SHORT TERM...LEWIS
LONG TERM...SKIPPER
AVIATION...LEWIS


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