Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 281037
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
637 AM EDT SUN SEP 28 2014

.SYNOPSIS...
ISSUED AT 432 AM EDT SUN SEP 28 2014

HIGH PRESSURE OVER THE GREAT LAKES WILL MOVE SLOWLY SOUTH TODAY AND
TONIGHT AND CONTINUE TO CAUSE FAIR WEATHER ACROSS OUR AREA. HIGHS
WILL BE IN THE UPPER 70S TODAY... EXCEPT ONLY IN THE LOWER 70S NEAR
LAKE MICHIGAN. LOWS TONIGHT SHOULD BE IN THE LOWER 50S WITH PATCHY
FOG EXPECTED LATE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 432 AM EDT SUN SEP 28 2014

SHRTWV MOVG ESE INTO NRN ONTARIO WILL CAUSE CUT-OFF UPR LOW OVER
IA TO SHEAR OUT WITH SUBSEQUENT WK/MOISTURE STARVED UPR LEVEL TROF
MOVG ACROSS OUR CWA TONIGHT. SOUTHERLY WINDS ALOFT AND WK LIFT IN
ADVANCE OF THIS SYSTEM AND ON BACKSIDE OF STRONG RIDGE AXIS OVER
THE ERN SEABOARD WILL CONT TO SUPPORT CIRRUS MOVG INTO/FORMING
ACROSS THE AREA TODAY WITH DECREASING CLOUDINESS EXPECTED TONIGHT
AS TROF MOVES TO OUR EAST. CIRRUS EXPECTED TO BE SUFFICIENTLY
THIN/PATCHY TO ALLOW MIXING UP TO H85 RESULTING IN HIGHS IN THE
U70S ACROSS MOST OF THE AREA... THOUGH WILL BE COOLER NEAR LAKE
MICHIGAN WHERE LIGHT GRADIENT WILL ALLOW A LAKE BREEZE TO DEVELOP.
WITH CIRRUS DIMINISHING OVERNIGHT AND WK GRADIENT PERSISTING...
RADIATIONAL COOLING SHOULD CAUSE PATCHY FOG TO DEVELOP LATE AS
TEMPS FALL INTO THE L50S.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 432 AM EDT SUN SEP 28 2014

SOME CHALLENGES THIS PERIOD INCLUDE CHANCES FOR RAIN SHOWERS OVER
NORTHERN AREAS MONDAY NIGHT/EARLY TUESDAY AND THE AMOUNT OF COLD AIR
ADVECTION BEHIND THE ASSOCIATED COLD FRONT TUESDAY. ALSO...TIMING OF
A STRONGER FRONT AND ASSOCIATED WEATHER LOOMS AHEAD LATE THIS WEEK.
FOR EARLY IN THE PERIOD...RATHER ASTOUNDING DIFFERENCES EXISTED IN
EARLIER RUNS EARLY IN THE PERIOD BETWEEN THE ECMWF AND GFS REGARDING
THE STRENGTH... ORIENTATION AND TRACK OF AN UPPER LEVEL TROF OVER
THE WESTERN GREAT LAKES REGION AND SUBSEQUENT AMOUNT OF COLD AIR
ADVECTION BEHIND THE ASSOCIATED COLD FRONT. THE GFS HAS BEEN
TRENDING TOWARD THE ECMWF IN THIS REGARD...SO HAVE CONTINUED TO
TREND HIGHS DOWN TUESDAY. HIGHS TUESDAY MAY STILL BE TOO WARM. LEFT
A VERY SMALL CHANCE FOR SHOWERS MONDAY NIGHT OVER NORTHEAST AREAS...
HOWEVER...DRY AIR AND LIMITED SATURATION AND WEAK ISENTROPIC LIFT AS
WELL AS LESS THEN FAVORABLE UPPER LEVEL JET DYNAMICS SHOULD GREATLY
LIMIT ANY RAINFALL. OTHERWISE...A STRONGER SYSTEM SHOULD REACH THE
FORECAST AREA LATE IN THE WEEK. ISOLATED THUNDERSTORMS ARE
POSSIBLE...WITH THE BEST CHANCE FOR RAIN FROM THURSDAY AFTERNOON
INTO EARLY FRIDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 636 AM EDT SUN SEP 28 2014

BR/FG BECOMING MORE WIDESPREAD OVER THE AREA IN THE PAST HOUR. SBN
HAS REACHED CROSSOVER TEMP AND FWA 1BLO... THUS WILL CONT WITH BRIEF
PERIOD OF MVFR VSBYS IN SBN TAF AND IFR AT FWA EARLY THIS MORNING. VFR
CONDITIONS THE REST OF TODAY AND THIS EVENING WITH JUST SOME
CIRRUS FOR CLOUDS. CIRRUS SHOULD DIMINISH TONIGHT AS SHRTWV MOVES
EAST TO THE LWR GRTLKS. WITH LIGHT WIND FIELDS PERSISTING THIS
SHOULD SET THE STAGE FOR ANOTHER ROUND OF RADIATIONAL COOLING
FOG... WHICH GIVEN EXPECTATION OF LESS HIGH CLOUDINESS TONIGHT...
MAY HAVE A LITTLE GREATER IMPACT ON AVIATION THAN THIS MORNING`S
HAS.

&&

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

$$

SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...SKIPPER
AVIATION...JT


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