Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 211514
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1114 AM EDT THU MAY 21 2015

.SYNOPSIS...
ISSUED AT 1056 AM EDT THU MAY 21 2015

HIGH PRESSURE OVER THE REGION TODAY WILL GIVE GENERALLY A DRY DAY
WITH SOME SPRINKLES MOVING THROUGH THE CENTRAL PORTION OF THE
REGION. CLOUD COVERAGE WILL BE ON THE DECREASE THIS AFTERNOON
LEADING TO CLEAR TO MOSTLY CLEAR SKIES TONIGHT. DRY WEATHER FOR
TONIGHT EXCEPT FOR JUST THE NORTHEASTERN CORNER OF THE REGION
SEEING A CHANCE FOR SOME SPRINKLES. HIGHS TODAY WILL RANGE FROM
AROUND 60 IN THE SOUTH TO THE MIDDLE 60S IN SOUTHERN MICHIGAN.
LOWS TONIGHT WILL BE IN THE MIDDLE TO UPPER 40S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM EDT THU MAY 21 2015

BROAD SFC RIDGE CNTRD THROUGH THE CNTRL PLAINS WILL SHIFT EWD INTO
THE WRN LAKES TONIGHT. SECONDARY MSTR STARVED DISTURBANCE ROTATING
THROUGH BASE OF SW TROUGH THROUGH WRN QB MAY GENERATE A SPRINKLE OR
TWO AFT MIDNIGHT FAR NE AND RETAINED MENTION. OTRWS WX NIL THIS PD
WITHIN SFC RIDGE AXIS AS TEMPS BEGIN TO MODERATE.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 337 AM EDT THU MAY 21 2015

PICTURESQUE WEATHER FOR THE FIRST HALF OF THE UPCOMING HOLIDAY
WEEKEND AS SOUTHERN GREAT LAKES REMAIN ON THE SUBSIDENT DOWNSTREAM
SIDE OF BUILDING CENTRAL CONUS RIDGE. TEMPS WILL STILL BE SLIGHTLY
ON THE COOL SIDE OF CLIMO...ESPECIALLY ON FRIDAY WITH A FRESH PUSH
OF COOL...CANADIAN AIR BEHIND EXITING FRONTAL BOUNDARY.
HOWEVER...FULL MAY SUN AND VERY DRY LOW LEVELS WILL PROMOTE MIXING
TO AROUND 800MB. THIS SHOULD ALLOW AFTERNOON HIGHS TO CLIMB INTO THE
MID TO UPPER 60S FOR MOST LOCATIONS. CLOUDS BEGIN TO INCREASE ON
SATURDAY BUT THERMAL PROFILES ALSO MODERATE AND SHOULD CLIMB INTO
THE LOW TO MID 70S UNDER JUST PARTLY CLOUDY SKIES.

RIDGE AXIS SHIFTS EAST FOR THE LATTER HALF OF THE HOLIDAY WEEKEND
AND INCREASING SOUTHWEST FLOW/WAA WILL BRING INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS. STILL A HIGH DEGREE OF UNCERTAINTY
REGARDING HOW EXACTLY PIECEMEAL EJECTION OF WESTERN CONUS TROUGH
WILL UNFOLD. MODELS HAVE BEEN TRENDING SLOWER...A COMMON OCCURRENCE
IN THESE HIGHLY AMPLIFIED PATTERNS...AND LATEST GFS ACTUALLY KEEPS
US DRY THROUGH SUNDAY NIGHT WITH MAIN BELT OF ISENTROPIC ASCENT
FOCUSED WELL TO OUR NORTH. LATEST 00Z GFS EVEN SHOWS A MORE SUBDUED
(AND LIKELY MORE REALISTIC) DEPICTION OF CONVECTION COVERAGE FOR
MONDAY AND TUESDAY. ECMWF PAINTS A VERY DIFFERENT PICTURE BUT STILL
KEEPS US DRY UNTIL SUNDAY AFTERNOON. PREFER TO LEAN ON THE DRIER GFS
GIVEN POOR PERFORMANCE OF MODEL QPF IN SIMILAR PATTERNS OF LATE.
SEEMS AS THOUGH STUBBORN EASTERN CONUS RIDGE IS A SERIOUS HINDRANCE
TO ANY PRECIP ABSENT ANY WELL DEFINED SHORTWAVES LIFTING NORTHEAST.
NOT THAT WE WONT HAVE THESE SUBTLE WAVES PASSING THROUGH AT TIMES
EARLY NEXT WEEK BUT AS PREVIOUSLY DISCUSSED...PRECIP COVERAGE AND
TIMING WILL DEPEND ON EXACTLY WHEN AND WHERE THESE WAVES PASS AND
THAT IS IMPOSSIBLE TO NAIL DOWN MORE THAN A DAY OR TWO IN ADVANCE.
KEPT SOME LOW END LIKELY POPS IN OUR NORTHWEST AND IT WILL PROBABLY
RAIN AT SOME POINT EARLY NEXT WEEK BUT AGAIN...NOT EXPECTING A
WASHOUT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 648 AM EDT THU MAY 21 2015

VFR CONDS WILL CONT THROUGH THE PD. CLRG LINE ACRS SE WI WILL CONT
TO ADV SLOWLY SEWD THROUGH THIS MORNING. OTRWS SOME MARGINALLY
GUSTS WINDS AOA 15KTS XPCD AT KSBN THIS AFTN AS SFC BASE MIXED LYR
MAXIMIZES.


&&

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

$$

SYNOPSIS...LOTHAMER
SHORT TERM...T
LONG TERM...AGD
AVIATION...T


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