Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 270546
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
146 AM EDT SAT JUN 27 2015

.SYNOPSIS...
ISSUED AT 822 PM EDT FRI JUN 26 2015

AN AREA OF LOW PRESSURE WILL MOVE FROM SOUTH CENTRAL INDIANA TO
NORTHEAST OHIO BY MIDDAY SATURDAY AND INTENSIFY. THIS SYSTEM WILL
BRING MODERATE TO HEAVY RAIN TO MUCH OF THE FORECAST AREA. AREAS
ALONG AND SOUTH OF ROUTE 24 WILL SEE THE MOST RAIN...AND POTENTIAL
FOR FLASH FLOODING. THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL. LOWS TONIGHT WILL BE AROUND 60. SATURDAY WILL BE COOLER
AND WINDY...WITH HIGHS IN THE MID TO UPPER 60S. RAIN SHOWERS AND
ISOLATED THUNDERSTORMS WILL PERSIST MAINLY EAST OF INTERSTATE 69
ON SATURDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 338 PM EDT FRI JUN 26 2015

HEAVY RAIN AND FLOODING IS THE PRIMARY CONCERN FOR THE SHORT TERM
PERIOD AS AN UNSEASONABLY STRONG LOW PRESSURE CENTER TRACKS
THROUGH THE OHIO VALLEY. THIS HIGHLY DYNAMIC SYSTEM COUPLED WITH
PWAT VALUES ABOVE THE 90TH PERCENTILE HAS SET THE STAGE FOR
SEVERAL INCHES OF RAIN ACROSS THE SOUTHERN PORTION OF OUR FORECAST
AREA. UNFORTUNATELY THOSE AREAS HAVE ALREADY SEEN RECORD SETTING
RAINFALL SO FAR IN THE MONTH OF JUNE AND THEREFORE...FLOODING
CONCERNS ARE HIGH.

DIFFUSE SURFACE LOW EXTENDING FROM NEAR KIND TO NORTHERN TEXAS
WILL DEEPEN THIS EVENING ACROSS SOUTHERN ILLINOIS AND TRACK
THROUGH SOUTHERN INDIANA OVERNIGHT. THE RAPID DEEPENING OF THIS
LOW (~9MB/12HR) WILL LEAD TO MAXIMIZED ISENTROPIC LIFT IN OUR FAR
SE CWA...ALONG THE TRACK OF THE 700MB LOW. IN ADDITION TO THE
STRONG DYNAMICS ASSOCIATED WITH THIS SYSTEM...THE UPPER LOW WILL
CUT OFF OVER NORTHERN OHIO ON SATURDAY AND SLOW THE FORWARD
PROGRESSION OF THE LOW CONSIDERABLY. THEREFORE...WHEREVER THE
PIVOT POINT SETS UP NW OF THE LOW TRACK...SIGNIFICANT FLOODING IS
LIKELY. INCREASED QPF SE OF US24 WHERE HEAVY RAIN IS ALREADY
FALLING AND THE PIVOT POINT IS LIKELY TO SET UP. IT IS WORTH
MENTIONING THAT MOST OF THE HIGH RESOLUTION GUIDANCE IS INDICATING
STORM TOTAL RAINFALL AMOUNTS OF 4 TO 5 INCHES OR MORE WHICH
CERTAINLY IS NOT OUT OF THE QUESTION AND WOULD INDICATE THAT
SOMEWHERE WITHIN THE FLASH FLOOD WATCH AREA IS LIKELY TO SEE IN
EXCESS OF 3 INCHES OF RAIN.

AS THIS LOW PRESSURE CENTER DEEPENS...NORTHERLY WINDS WILL
INCREASE THROUGH THE DAY ON SATURDAY WITH AFTERNOON WIND GUSTS IN
EXCESS OF 35MPH EXPECTED. GIVEN THE EXTREMELY WET SOILS IN OUR
EASTERN COUNTIES WHERE WINDS WILL BE MAXIMIZED...WOULD NOT BE
SURPRISED BY AN ISOLATED REPORT OF AN UPROOTED TREE IN THAT AREA
TOMORROW.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 338 PM EDT FRI JUN 26 2015

UNUSUALLY AMPLIFIED PATTERN FOR THIS TIME OF YEAR WILL CONTINUE
THROUGH THE EXTENDED PERIOD FEATURING WESTERN US RIDGE AND EASTERN
TROF WITH 500MB HT ANOMALIES AVERAGING +150M AND -100M
RESPECTIVELY. FORECAST PERIOD TO BEGIN WITH DEEP CLOSED UPPER LOW
EXITING TO THE EAST LEAVING JUST A SMALL CHANCE OF LINGERING
PRECIP AT THE ONSET OF THE FCST PERIOD SATURDAY EVENING. LARGE
SCALE TROF AXIS REMAINS OVER THE REGION AND WILL PROVIDE ONLY A
SMALL WINDOW OF DRY WX ON SUNDAY. NEXT SHORT WAVE WILL BE DROPPING
DOWN INTO THE NORTHERN GREAT LAKES ON SUNDAY AND BRING A WEAK
SURFACE WAVE INTO THE AREA BY SUNDAY EVENING. AS EXPECTED...MODELS
OFFER VARYING SOLNS ON TIMING AND INTENSITY BUT GENERALLY SUGGEST
KEEPING SUNDAY DRY AND HOLD OFF TILL 00Z MON TO BRING POPS BACK
IN. THIS SYSTEM WILL WORK ITS WAY ACROSS THE CWA ON MONDAY
BRINGING WIDESPREAD BUT GENERALLY LIGHT TO MODERATE
RAINFALL...WITH A CHANCE OF CONVECTIVE ELEMENTS EMBEDDED WITHIN.
GIVEN THE CURRENT WET PATTERN SEE NO REASON TO GO ALONG WITH THE
CONSENSUS GUIDANCE AND CARRY LIKELY POPS. DAYS 5-7 BECOME
CHALLENGING AS MEDIUM RANGE MODELS ATTEMPT TO BRING CANADIAN HIGH
PRESSURE INTO THE NORTHERN GREAT LAKES REGION AND SET UP A STRONG
BAROCLINIC ZONE ON ITS SOUTHERN PERIPHERY. UNCERTAINTY LIES IN
WHERE THIS BOUNDARY WILL SET UP...LATEST MODEL RUNS HINTING AT A
MORE SOUTHERLY SOLN AND POTENTIALLY KEEPING A MAJORITY OF THE CWA
DRY UNTIL THE MAIN SURFACE WAVE EJECTS INTO THE OHIO VALLEY TOWARD
THE END OF THE FCST PERIOD. AS EXPECTED...SUPERBLEND WASHES OUT
VARYING SOLNS INTO SMALL CHANCE POPS EVERY SINGLE PERIOD THRU DAY
7. CURRENT GRIDS REFLECT THIS AND WILL RELUCTANTLY YIELD TO THIS
SOLN PENDING A STRONGER MODEL SIGNAL FOR DRY WX. TEMPERATURES WILL
REMAIN AT OR SLIGHTLY BELOW NORMAL THROUGH DAY 7.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 146 AM EDT SAT JUN 27 2015

SHARP CONTRAST CONTINUES BETWEEN KSBN AND KFWA OVERNIGHT AS HIGHLY
DYNAMIC SYSTEM WRAPS UP ACROSS CENTRAL INDIANA. DRIER LOW LEVEL
AIR HOLDING AT KSBN AND...WHILE A FEW PERIODS OF MVFR CONDITIONS
MAY BE POSSIBLE EARLY THIS MORNING...EXPECT PRIMARILY VFR
CONDITIONS THROUGH THE PERIOD. AT KFWA...BETTER FORCING AND LOW
LEVEL MOISTURE CLOSER TO THE SURFACE LOW/FRONT SHOULD LEAD TO
WORSENING CONDITIONS DURING THE NEXT FEW HOURS. SEVERAL OBS JUST
UPSTREAM ARE IFR AND FORECAST SOUNDINGS/MOS GUIDANCE SUGGEST IFR
POSSIBLE AS WELL. CONDITIONS WILL THEN GRADUALLY IMPROVE AFTER
SUNRISE AS LOW PRESSURE CENTER PULLS EASTWARD AND DRIER AIR
ADVECTS SOUTHWARD. GUSTY NORTH WINDS EXPECTED TO PERSIST THROUGH
THE DAY THOUGH.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FLASH FLOOD WATCH UNTIL 10 AM EDT THIS MORNING FOR INZ018-
     022>027-032>034.

MI...NONE.
OH...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR OHZ004-005-015-016-
     024-025.

LM...NONE.
&&

$$

SYNOPSIS...MURPHY
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...AGD


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