Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 271724
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
124 PM EDT MON JUL 27 2015

.SYNOPSIS...
ISSUED AT 345 AM EDT MON JUL 27 2015

THE WARM WEATHER WILL CONTINUE TODAY WITH MAINLY DRY CONDITIONS
DUE TO PERSISTENT HIGH PRESSURE. AN UPPER LEVEL RIDGE OF HIGH
PRESSURE WILL BUILD ACROSS THE REGION TONIGHT INTO TUESDAY
PROVIDING WARM AND HUMID CONDITIONS TUESDAY AFTERNOON. A COLD
FRONT WILL APPROACH THE AREA BY WEDNESDAY PROVIDING THE NEXT
CHANCE OF SHOWERS AND THUNDERSTORMS. HIGH TEMPERATURES THIS
AFTERNOON WILL REACH INTO THE MID 80S WITH A FEW SPOTS REACHING
INTO THE UPPER 80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO
THE MID 60S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM EDT MON JUL 27 2015

A RELATIVELY QUIET DAY IS SHAPING UP FOR MONDAY...WITH MAIN
FORECAST CHALLENGE RESOLVING ANY LOW END/ISOLATED AFTERNOON SHOWER
OR THUNDERSTORM CHANCES ACROSS THE FAR SOUTH.

IN THE VERY NEAR TERM...SHOULD SEE SOMEWHAT OF A REPEAT IN TERMS OF
PATCHY FOG POTENTIAL EARLY THIS MORNING...ALTHOUGH SHORT TERM
RAP/NAM FORECAST SOUNDINGS SUGGEST SLIGHTLY LESS FAVORABLE
HYDROLAPSE PROFILES IN TERMS OF A MORE SIGNIFICANT PATCHY DENSE
FOG POTENTIAL COMPARED TO 24 HOURS AGO. ALREADY STARTING TO SEE A
FEW SITES HEAD DOWN HOWEVER...WITH VALPARAISO REPORTING 1/2SM AT
07Z. WILL MAINTAIN PATCHY FOG MENTION THIS MORNING WITH SIMILAR
RAPID BURNOFF AFTER 12Z.

OTHERWISE FOR TODAY...LOCAL AREA WILL REMAIN ON SOUTHERN PERIPHERY
OF GREAT LAKES ANTICYCLONE WITH PRONOUNCED INSTABILITY GRADIENT
ANCHORED ACROSS SOUTHWEST HALF OF THE AREA. A VERY WEAK MID/UPPER
LEVEL TROUGH MEANDERING ACROSS THE OHIO VALLEY COMBINED WITH
WEAKLY CONFLUENT LOW LEVEL FLOW MAY GIVE RISE TO AN ISOLATED
SHOWER OR THUNDERSTORM PARTICULARLY FOR LOCATIONS JUST SOUTH OF
FORECAST AREA ACROSS CENTRAL INDIANA. WITH NORTHERN EXTENT OF THIS
VERY WEAK MID/UPPER LEVEL FORCING POSSIBLY CLIPPING EXTREME SOUTH
CENTRAL PORTIONS OF FORECAST AREA AND WEAK AFTERNOON INSTABILITY
(500-1000 J/KG SB CAPES) HAVE CONFINED ANY ISOLATED MENTION JUST
TO EXTREME SOUTH CENTRAL. IF ANY ISOLATED SHOWER OR STORMS ARE
ABLE TO FORM AS FAR NORTH AS LOCAL FORECAST AREA...THEY SHOULD
QUICKLY DIMINISH IN THE 22Z-00Z TIMEFRAME.

ANOTHER WARM AND HUMID DAY IS IN STORE WITH HIGHEST HEAT INDICES IN
THE SOUTHWEST THIRD OF THE AREA DUE TO ORIENTATION OF NEAR SFC/LOW
LEVEL THETAE GRADIENT WHERE PEAK AFTERNOON HEAT INDICES MAY REACH
INTO THE LOWER 90S. HIGH TEMPS SHOULD BE A FEW DEGREES WARMER TODAY
FOR MOST LOCATIONS DUE TO BETTER INSOLATION WITH POSSIBLE
EXCEPTION ACROSS THE FAR SOUTH WHERE MID LEVEL CLOUDS MAY BE OF A
BIT GREATER COVERAGE. QUIET CONDITIONS EXPECTED TONIGHT AS UPPER
RIDGE AXIS ACROSS MID MS RIVER VALLEY SLOWLY TRANSLATES EASTWARD
WITH LOWS GENERALLY IN THE MID 60S.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 345 AM EDT MON JUL 27 2015

HOT AND HUMID CONDITIONS WILL PREVAIL AT THE START OF THE
PERIOD AS HIGH PRESSURE CONTINUES TO DRIFT EAST. UPPER LEVEL
TROUGH AND ASSOCIATED SFC FRONT STILL POISED TO IMPACT THE REGION
POSSIBLY AS SOON AS LATE TUESDAY NIGHT WITH BEST CHANCE DURING THE
DAY WEDNESDAY. MODELS SEEM TO BE COMING INTO A TOUCH BETTER
AGREEMENT BUT STILL LEANING TOWARDS AT LEAST SCATTERED SHOWERS AND
STORMS. SEVERE THREAT WITH THIS SYSTEM NOT OVERLY IMPRESSIVE WITH
BEST UPPER DYNAMICS REMOVED TO THE NORTH AS WELL AS POTENTIAL FOR
CONVECTIVE DEBRIS FROM OVERNIGHT CONVECTION AND ALSO EARLY TIMING
OF THE FRONT THROUGH MUCH OF THE AREA BY MID TO LATE AFTERNOON.
SWODY3 PLACED EASTERN PORTIONS IN A MARGINAL RISK...WHICH IS
PLAUSIBLE.

IN THE WAKE OF THE FRONT...COOLER AND LESS HUMID CONDITIONS WILL
MOVE BACK IN. HOWEVER...REGION WILL REMAIN UNDER A NW FLOW ALOFT
WITH A SERIES OF WEAK DISTURBANCES SET TO MOVE IN EVERY DAY OR 2.
THIS RESULTS IN THE EXTENDED GUIDANCE PLASTERING THE AREA WITH SLGT
CHC AND CHC POPS THROUGH THE END OF THE PERIOD. THE THURSDAY THROUGH
SUNDAY PERIOD DOESN`T LOOK LIKE A WASHOUT IN ANY FASHION...BUT WITH
TIMING AND COVERAGE HARD TO PIN DOWN THAT FAR OUT AND SIGNALS AT
LEAST THERE FOR SOME POPS...HAVE NO CHOICE BUT TO KEEP GRIDS SIMILAR
TO LAST FORECAST. BEST CHANCE WOULD APPEAR TO BE SUNDAY AND SUNDAY
NIGHT WHEN SOMEWHAT STRONGER WAVE DOES DROP OUT OF CANADA.
TEMPERATURES WILL REMAIN NEAR OR ABOVE NORMAL THROUGH THE PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 122 PM EDT MON JUL 27 2015

VFR CONDITIONS THROUGH PERIOD. EASTERLY WINDS UNDER 10 KTS.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...FISHER
AVIATION...LEWIS


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