Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 190534
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
134 AM EDT SUN APR 19 2015

.SYNOPSIS...
ISSUED AT 755 PM EDT SAT APR 18 2015

CLOUDS WILL GRADUALLY INCREASE OVERNIGHT AS A FRONTAL SYSTEM
RACES NORTHWARD FROM THE LOWER MISSISSIPPI VALLEY AND INTO
NORTHERN INDIANA BY SUNDAY AFTERNOON. A MORE STEADY RAIN WILL
MOVE IN SUNDAY AFTERNOON AND CONTINUE INTO SUNDAY NIGHT. A FEW
ISOLATED EMBEDDED THUNDERSTORMS ARE ALSO POSSIBLE SUNDAY
AFTERNOON. LOWS TONIGHT WILL RANGE FROM THE MID 40S TO LOWER 50S.
SUNDAY WILL MARK THE START OF A COOLING TREND WITH HIGHS IN THE
60S.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 435 PM EDT SAT APR 18 2015

MOISTURE HAS POOLED ALONG THE SOUTHERN THIRD OF THE FORECAST AREA
AND SURFACE TROF / FRONTAL BOUNDARY HAS PUSHED OUT OF
MICHIGAN...EVIDENT ON RADAR. INSTABILITY AND CONVERGENCE ALONG
AND SOUTH OF THIS BOUNDARY HAS TRIGGERED ISOLATED THUNDERSTORMS
SOUTH OF US-30. EXPECT TO SEE ADDITIONAL DEVELOPMENT AS THE
EASTERLY FLOW AND CONVERGENCE INCREASE OVER THE NEXT FEW HOURS.

CONVECTION WILL END AS THE INSOLATION DECREASES AND SHOULD HAVE A
QUICK DECREASE IN COVERAGE.

HIGH PRESSURE GRADUALLY RETREATING THROUGH SUNDAY MORNING.
APPROACHING SYSTEM WITH ABUNDANT CIRRUS SHIELD WILL CONTINUE TO
OVERSPREAD THE REGION AND WITH DEEPENING EASTERLY FLOW...BOUNDARY
LAYER MOISTURE WILL BE SHIFTED SOUTH AND WEST OVERNIGHT...AND
EXPECT THIS TO BE SLOW TO RETURN TO THE NORTHERN TWO-THIRDS OF
THE AREA UNTIL SUNDAY MORNING.

MUCH COOLER DAY SUNDAY AS THE CLOUDS AND PRECIPITATION OVERSPREAD
THE REGION.

&&

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 435 PM EDT SAT APR 18 2015

A SECOND SYSTEM IMMEDIATELY FOLLOWING THE EJECTING SOUTHWESTERN
SHORTWAVE WILL MOVE ACROSS THE AREA EARLY MONDAY. FOLLOWED A GFS
SOLUTION WHICH HAS TRENDED THIS SYSTEM SLOWER. THIS TREND APPEARS
REASONABLE WITH A DEEP DIGGING UPPER TROF AND A 90 KNOT UPPER JET
ON THE BACK SIDE OF THIS SYSTEM. THEREFORE...HAVE ADJUSTED THE
TIMING OF RAIN CHANCES SUNDAY NIGHT AND MONDAY. ISENTROPIC 300K
SURFACE SUPPORTS THE BEST RAIN CHANCES MONDAY MORNING. A LITTLE
BREAK IN THE SHOWERS IS POSSIBLE AFTER MIDNIGHT SUNDAY NIGHT.

AFTER THIS SYSTEM...MUCH COOLER AIR WILL MOVE INTO THE AREA FOR
THE REST OF THE WEEK AS A COLD CORE UPPER LOW BECOMES QUASI
STATIONARY NEAR OR JUST NORTH OF LAKE SUPERIOR. TEMPERATURES WILL
BE BELOW NORMAL FROM TUESDAY THROUGH THE END OF THE WEEK AS MUCH
COLDER AND DRIER AIR SPREADS INTO THE AREA. CONTINUED TO CUT
SUPERBLEND RAIN CHANCES. ALTHOUGH VERY CHILLY AIR ALOFT WITH
ALLOW IMPRESSIVE LAPSE RATES OF 9 TO 10C/KM FROM THE SURFACE TO
750 MB...VERY DRY AIR IN THE LOW LEVELS WITH DEW POINTS IN THE
MID 20S TO LOWER 30S WILL PROBABLY BE TOO DRY TO SUPPORT MUCH
MORE THAN ISOLATED SHOWERS. EXPECT HIGHS DURING THIS PERIOD IN
THE LOW TO MID 50S WITH LOWS IN THE LOW TO MID 30S. KEPT THE
MENTION OF FROST OUT FOR NOW GIVEN UNCERTAINTY OF THE TIMING AND
LOCATION OF LINGERING CLOUDS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 134 AM EDT SUN APR 19 2015

VFR CONDITIONS WILL PERSIST THROUGH THE MORNING BEFORE A PIECE OF
THE UPPER LOW CURRENTLY OVER THE SOUTHERN PLAINS LIFTS NORTHEAST
INTO OUR AREA DURING THE AFTERNOON. STRONG SURGE OF MOISTURE AND
GOOD SYNOPTIC FORCING WILL BRING RAPIDLY DETERIORATING CONDITIONS
AND MODERATE RAIN TO THE TERMINALS BEGINNING AROUND 21Z. HELD WITH
LOW END MVFR FOR NOW BUT PERIODS OF IFR CEILINGS WILL BE POSSIBLE
IN THE 00-06Z TIMEFRAME. AN ISOLATED THUNDERSTORM MAY ALSO BE
POSSIBLE BUT CHANCES ARE FAR TOO LOW FOR INCLUSION IN THE TAF.

&&

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

$$

SYNOPSIS...MCD
SHORT TERM...LEWIS
LONG TERM...SKIPPER
AVIATION...AGD


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