Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 231943
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
343 PM EDT SAT MAY 23 2015

.SYNOPSIS...
ISSUED AT 118 PM EDT SAT MAY 23 2015

HIGH PRESSURE WILL KEEP SKIES MOSTLY CLEAR AND CONDITIONS DRY
THROUGH TONIGHT. SHOWER AND THUNDERSTORM CHANCES WILL INCREASE
LATE SUNDAY THROUGH MEMORIAL DAY. WARMER TEMPERATURES ARE EXPECTED
THIS WEEKEND THROUGH NEXT WEEK...WITH HIGHS NEAR 80 DEGREES EACH
DAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 341 PM EDT SAT MAY 23 2015

RELATIVELY BENIGN SHORT TERM PERIOD WX WISE...AS SFC RIDGING
CENTERED EAST OF THE AREA THIS AFTERNOON CONTINUES TO SLIDE EAST
INTO THE ATLANTIC OCEAN. BERMUDA UPPER RIDGING WILL AMPLIFY INTO THE
EASTERN CONUS THROUGH SUNDAY...W/ RETURN FLOW INCREASING INTO THE
REGION. BROAD WRN CONUS TROF ENERGY WILL BEGIN TO EJECT NE THROUGH
THE PLAINS INTO THE WRN GREAT LAKES ON SUNDAY. KEPT SLIGHT CHANCE
POPS ACROSS WESTERN AREAS SUNDAY AFTN AS SUBTLE 925/850MB MOISTURE
GRADIENT/TROF LIFTS INTO WRN PORTIONS OF THE AREA. FORCING FOR
ASCENT IS PALTRY ALONG THIS FEATURE...AND ALTHOUGH MODEL SOUNDINGS
HINT AT VERY WEAK INSTABILITY IN THE 700-500MB LAYER...MEAGER LAPSE
RATES AND DRIER SUB CLOUD LAYER SHOULD LIMIT MORE WIDESPREAD
RAINFALL FROM THE 18Z-00Z SUNDAY TIMEFRAME....SO SLIGHT CHANCE POPS
WILL SUFFICE ATTM.

&&

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 341 PM EDT SAT MAY 23 2015

LEAD SHORT WAVE LIFTING ACROSS THE SOUTHERN GREAT LAKES SUNDAY NIGHT
WILL BE ACCOMPANIED BY LOW/MID LEVEL THETAE SURGE. STILL SOME
QUESTIONS REGARDING MOISTURE IN LOWEST 5K FT FOR SUNDAY
EVENING...WITH NAM/GFS BUFFER SOUNDINGS STILL SUGGESTING SOME
RESPECTABLE LOW LEVEL DEW POINT DEPRESSIONS. GIVEN WEAK NATURE OF
FORCING HAVE MAINTAINED JUST LOW CHANCE/SLIGHT CHANCE POPS WITH THIS
WARM FRONTAL FEATURE...AND MENTIONED JUST SLIGHT CHANCE TS GIVEN
HIGHLY ELEVATED AND WEAK NATURE TO INSTABILITY. BREAK IN PRECIP
CHANCES MAY EVOLVE LATER SUNDAY EVENING AS THIS WARM FRONTAL
BOUNDARY LIFTS NORTH OF THE AREA...ALTHOUGH EXPECTING A MORE
SUBSTANTIAL SYNOPTIC SCALE SHORT WAVE TO EJECT NORTHEAST ACROSS THE
MID MS VALLEY LATE SUNDAY NIGHT THAT COULD SPREAD RAIN CHANCES BACK
ACROSS MAINLY WESTERN PORTIONS OF THE AREA BY MONDAY MORNING.

HAVE ALSO CONTINUED LOW TO MID RANGE CHANCE POPS FOR MONDAY AS THIS
SYNOPTIC WAVE MOVES THROUGH THE AREA. SOME INDICATIONS THAT THE BULK
OF THIS FORCING MAY SHIFT EAST OF THE AREA BY THE MID TO LATE
AFTERNOON HOURS...ALONG WITH A CORRESPONDING EASTWARD SHIFT TO
DEEPER MOISTURE. HAVE NOT ADDED MUCH IN THE WAY OF TEMPORAL DETAIL
TO POPS MONDAY...WITH STILL LOW CONFIDENCE IN TIMING THE EASTWARD
PROGRESSION OF THE WEAK MID/UPPER LEVEL WAVE. EXTENT OF THUNDER ON
MONDAY MAY BE SOMEWHAT LIMITED BY CONTINUED MEAGER MID LEVEL LAPSE
RATES. A LULL IN PRECIP CHANCES IS EXPECTED MONDAY EVENING...BEFORE
A STRONGER SYNOPTIC WAVE SHEARS ACROSS THE SOUTHERN GREAT LAKES
REGION FOR TUESDAY. SHOULD SEE A RENEWED LOW LEVEL THETAE ADVECTIVE
SURGE AHEAD OF THIS FEATURE BY TUESDAY MORNING AND HAVE MAINTAINED
HIGH CHANCE POPS FOR TUESDAY. SOME MODEST INCREASE IN MID/UPPER FLOW
SHOULD ACCOMPANY THIS WAVE...BUT CONTINUED MARGINAL MID LEVEL LAPSE
RATES STILL ARGUES FOR LOW SEVERE THREAT. ABOVE NORMAL TEMPS TO
CONTINUE FOR MONDAY-TUESDAY WITH HIGHS IN UPPER 70S TO LOWER 80S AND
LOWS GENERALLY IN THE LOWER TO MID 60S.

PREDICTABILITY DIMINISHES SOMEWHAT FROM MID WEEK AND BEYOND AS MID
LEVEL HEIGHTS RISE ONCE AGAIN THE WAKE OF THIS DEPARTING SHORT WAVE.
HOWEVER WITH SEVERAL SMALLER SCALE DISTURBANCES RIPPLING THROUGH THE
FLOW AND DIURNAL INSTABILITY...DIFFICULT TO COMPLETELY REMOVE POPS
FOR ANY EXTENDED PERIODS. THUS...HAVE MAINTAINED BROADBRUSH LOW POPS
THROUGH MUCH OF THE DAY 5-7 PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 118 PM EDT SAT MAY 23 2015

VFR CONDITIONS CONTINUE THROUGH THE PERIOD W/ SFC RIDGING EAST OF
THE REGION. MID LVL CLOUD COVER WILL BE ON THE INCREASE TOWARD THE
END OF THE PERIOD AS NEXT SYSTEM APPROACHES THE REGION. LIGHT
SOUTHERLY WINDS EXPECTED THROUGH THE PERIOD.

&&

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

$$

SYNOPSIS...NG
SHORT TERM...NG
LONG TERM...MARSILI
AVIATION...NG


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