Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 241029
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
629 AM EDT FRI JUL 24 2015

.SYNOPSIS...
ISSUED AT 321 AM EDT FRI JUL 24 2015

HIGH PRESSURE WILL CONTINUE TO PROVIDE DRY WEATHER AND SEASONABLE
TEMPERATURES TODAY AND TONIGHT. THIS HIGH WILL SHIFT OFF TO THE
EAST FOR SATURDAY AS AN UPPER LEVEL DISTURBANCE APPROACHES THE
GREAT LAKES REGION. THIS WILL RESULT IN A CHANCE OF SHOWERS AND
THUNDERSTORMS SATURDAY AND SATURDAY NIGHT. A CHANCE OF SHOWERS AND
THUNDERSTORMS MAY LINGER INTO SUNDAY...ESPECIALLY ACROSS PORTIONS
OF NORTHWEST AND WEST CENTRAL INDIANA. HIGH TEMPERATURES THIS
AFTERNOON WILL REACH INTO THE MID 80S...WITH LOW TEMPERATURES
TONIGHT DROPPING BACK INTO THE MID 60S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM EDT FRI JUL 24 2015

QUIET WEATHER WILL CONTINUE TODAY AND TONIGHT AS A BROAD LOW
LEVEL ANTICYCLONE CONTINUES TO BE THE MAIN FEATURE. THE VERY WEAK
W-E ORIENTED LOW LEVEL THERMAL TROUGH ACROSS THE OHIO VALLEY WILL
CONTINUE TO MODIFY AND SHIFT SOUTHEAST TODAY AS MID/UPPER LEVEL
RIDGE AXIS APPROACHES THE WESTERN GREAT LAKES. THIS WILL ALLOW FOR
CONTINUED SLIGHT MODIFICATION OF LOW LEVEL AIR MASS. BACKGROUND
SYNOPTIC SUBSIDENCE SHOULD LIMIT EXTENT OF DIURNAL CU
SOMEWHAT...WITH A GOOD DEAL OF INSOLATION AND MOSTLY SUNNY TO
PARTLY CLOUDY SKIES EXPECTED. FORECAST SOUNDINGS DO SUGGEST A BIT
BETTER MIXING TODAY AS SFC HIGH PRESSURE BEGINS TO SLIDE TO THE
SOUTHEAST. GIVEN THE ABOVE FACTORS HAVE CONTINUED TREND FROM
PREVIOUS FORECAST WITH HIGHS GENERALLY 2 TO 4 DEGREES WARMER THAN
YESTERDAY PUTTING MOST LOCATIONS SOLIDLY IN THE MID 80S THIS
AFTERNOON. MODEST INCREASE IN THE SOUTH SOUTHWEST GRADIENT SHOULD
KEEP ANY LAKE BREEZE IMPACT CONFINED TO IMMEDIATE SHORELINE WITH
BEST CHANCE OF SOME INLAND PENETRATION ACROSS NORTHERN BERRIEN
COUNTY.

FOR TONIGHT...UPPER LEVEL SHORT WAVE WORKING ACROSS THE NORTHERN
HIGH PLAINS THIS MORNING WILL BEGIN TO DAMPEN UPPER RIDGING ACROSS
THE GREAT LAKES. VEERING OF LOW LEVEL FLOW IN ADVANCE OF PRE-FRONTAL
TROUGH FEATURE LATE TONIGHT ACROSS THE WESTERN GREAT LAKES WILL
PROMOTE STRONGER LOW LEVEL MOISTURE ADVECTION TOWARD DAYBREAK ACROSS
NORTHWEST THIRD OF THE FORECAST AREA. INHERITED SLIGHT CHANCE
POPS AFTER 09Z GIVEN SOME WEAK ELEVATED INSTABILITY DEVELOPING
WITH APPROACH OF PREFRONTAL TROUGH STILL SEEM REASONABLE AND NO
SIGNIFICANT CHANGES MADE.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 321 AM EDT FRI JUL 24 2015

SHRTWV MOVG OVER TOP OF SRN PLAINS RIDGE EXPECTED TO MOVE ACROSS THE
GRTLKS SAT-SAT NGT WITH ASSOCIATED WK CDFNT MOVG THROUGH OUR AREA.
MODERATE INSTABILITY...RELATIVELY DRY AIR ALOFT... AND AROUND 30KT 0-
6KM SHEAR EXPECTED ALONG/AHEAD OF THE CDFNT WHICH COULD RESULT IN A
FEW STORMS WITH HAIL AND STRONG GUSTY WINDS IN OUR AREA IF STORMS DO
DVLP WHICH IS QUESTIONABLE GIVEN FCST WK FORCING/CAPPING. FRONT
EXPECTED TO STALL FM THE OH VALLEY W-NW TO THE CENTRAL/NRN PLAINS
SUN-MON. TSTMS MAY DEVELOP ALONG/NORTH OF THIS BOUNDARY OVER THE NRN
PLAINS AND TRACK SEWD INTO OUR AREA IN THIS TIMEFRAME WITH HIGHEST
CHANCES SW PORTION OF CWA CLOSER TO STALLED SFC BOUNDARY WHERE
GREATER MOISTURE/INSTABILITY/FORCING SHOULD BE PRESENT. UPR RIDGE
OVER THE PLAINS EXPECTED TO MOVE EAST INTO THE GRTLKS TUE-WED AS A
DEEP TROF MOVES THROUGH THE NRN ROCKIES AND INTO THE NRN PLAINS.
STILL SOME POTENTIAL FOR TSTMS TUE ON NE PERIPHERY OF UPR RIDGE BUT
CHANCES INCREASE WED AS UPR TROF APPROACHES THE GRTLKS WITH
DECREASING CHANCES BY THU AS THE TROF MOVES TO THE EAST. TEMPS
SHOULD GENERALLY BE ABOVE NORMAL WITH A SLOW WARMING TREND EXPECTED
INTO EARLY NEXT WEEK AS THE UPR RIDGE MOVES EAST... HWVR GIVEN PSBL
IMPACTS OF CONVECTION/CLOUDS... STAYED BLO MEX GUIDANCE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 556 AM EDT FRI JUL 24 2015

VFR CONDITIONS WILL PERSIST THROUGH THIS FORECAST PERIOD. SOME
REMNANT HIGH CLOUDINESS FROM UPPER MS VALLEY CONVECTION MAY WORK
INTO NORTHERN INDIANA TODAY...WITH OTHERWISE JUST SOME VFR
AFTERNOON CU DEVELOPING ONCE AGAIN. SLIGHT SOUTHEAST PROGRESSION
OF LOW LEVEL ANTICYCLONE WILL ALLOW SOUTH-SOUTHWEST WINDS TO
DEVELOP TODAY...BUT SPEEDS SHOULD REMAIN BELOW 10 KNOTS. UPPER
LEVEL SHORT WAVE TO APPROACH THE WESTERN GREAT LAKES TONIGHT WILL
ALLOW FOR BETTER PREFRONTAL MOISTURE ADVECTIVE SURGE LATE THIS
PERIOD...WITH A LOW END POTENTIAL OF A SHOWER OR THUNDERSTORM AT
KSBN AFTER 09Z AT KSBN DUE TO INCREASE IN ELEVATED INSTABILITY.
WILL KEEP TAFS DRY AT THIS TIME WITH GREATER POTENTIAL OF
ISOLATED STORMS HOLDING OFF UNTIL AFTER THIS FORECAST VALID
PERIOD.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...JT
AVIATION...MARSILI


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