Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 270545 CCA
AFDIWX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NORTHERN INDIANA
143 AM EDT WED MAY 27 2015

.SYNOPSIS...
ISSUED AT 143 AM EDT WED MAY 27 2015

A WEAK COLD FRONT IS EXPECTED TO MOVE ACROSS THE AREA THIS
AFTERNOON CAUSING SCATTERED SHOWERS AND THUNDERSTORMS. HIGH
PRESSURE WILL BUILD INTO THE AREA TONIGHT PROVIDING FAIR WEATHER.
HIGHS TODAY WILL BE IN THE UPPER 70S AND LOWER 80S... WITH LOWS
TONIGHT IN THE UPPER 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 302 PM EDT TUE MAY 26 2015

MUCH OF PRIOR UPDATE DISCUSSION REMAINS VALID. BREAK IN CLOUDS
ACROSS OUR EASTERN CWA EARLIER TODAY ALLOWED FOR MODEST
DESTABILIZATION WITH CURRENT SPC/RAP MESOANALYSIS INDICATING
AROUND 1000 J/KG OF SBCAPE. MULTIPLE LINES OF CONVECTION HAVE
DEVELOPED ACROSS INDIANA/ILLINOIS BUT MAIN THREAT WILL BE WITH THE
CLUSTER OF STORMS OVER CENTRAL INDIANA AS THEY MOVE
NORTHEAST...ALONG WITH ANY OTHER STORMS THAT MANAGE TO DEVELOP
AHEAD OF IT. INSTABILITY IS MARGINAL BUT DECENT SHEAR...ESPECIALLY
IN THE 0-3 KM LAYER WILL PRESENT A DAMAGING WIND THREAT WITH ANY
CLUSTERS THAT MANAGE TO DEVELOP MORE SIGNIFICANT UPDRAFTS. STILL
THINK THE RISK FOR WIDESPREAD/SIGNIFICANT SEVERE WEATHER IS LOW
BUT A FEW SCT STORMS MAY BECOME SEVERE AND AFTER COORDINATION WITH
SPC AND SURROUNDING OFFICES DECIDED TO GO AHEAD AND ISSUE A WATCH.
IT IS IN EFFECT UNTIL 10 PM BUT WILL LIKELY BE ABLE TO TRIM/CANCEL
A LITTLE BIT EARLIER THAN THAT.

EXPECT PRECIP TO EXIT BY LATE EVENING AND ONLY MINOR CHANGES TO
THE GOING FORECAST FOR TONIGHT AND TOMORROW. ANOTHER ROUND OF
THUNDERSTORMS POSSIBLE TOMORROW AFTERNOON IN OUR SOUTHEAST ZONES
BUT SEVERE CHANCES APPEAR LOW GIVEN MARGINAL INSTABILITY AND
SHEAR.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 302 PM EDT TUE MAY 26 2015

INCREASED PRECIPITATION CHANCES FRIDAY INTO SATURDAY HIGHLIGHT THE
LONG TERM PERIOD.

LITTLE CHANGES MADE FROM PREVIOUS FORECAST PACKAGE IN THE LONG TERM.
BROAD EAST COAST RIDING WILL KEEP ABOVE NORMAL TEMPERATURES ACROSS
THE REGION THROUGH THE END OF THE WEEK. SHARP NORTHERN STREAM
SHORTWAVE WILL DIG E/SE ACROSS NORTHERN ONTARIO FRIDAY...WITH
DEEPENING SFC CYCLONE NEAR JAMES BAY. THIS WILL PUSH A COLD FRONT
SOUTHEAST FRIDAY THROUGH SATURDAY. WITH AMPLE MOISTURE RETURN AND
DECENT SFC FORCING...WENT AHEAD AN RAISED POPS TO LIKELY FRIDAY
NIGHT THROUGH SATURDAY. SEVERE CHANCES AT THIS TIME ARE FAIRLY
LOW...WITH UNFAVORABLE DIURNAL TIMING WITH FROPA AND LITTLE UPPER
FLOW/SHEAR DESPITE MARGINAL INSTABILITY. WILL CONTINUE TO MONITOR
THROUGH THE WEEK FOR ANY CHANGES.

COOLER CONDITIONS WILL SETTLE INTO THE REGION AS AFOREMENTIONED
FRONT SINKS SOUTH OF THE FORECAST AREA SATURDAY INTO SUNDAY.
MAINTAINED CONSENSUS BLEND CHANCE/SLIGHT CHANCE POPS SATURDAY NIGHT
THROUGH MONDAY...HOWEVER THIS WILL LIKELY NEED TO BE REFINED FURTHER
IN SUBSEQUENT FORECAST RUNS. LATEST 12Z GFS HINTING AT SFC FRONT
SINKING SOUTH INTO THE OHIO RIVER VALLEY...WITH STRONG CANADIAN SFC
RIDGE SHUNTING SOUTHEAST THROUGH THE GREAT LAKES AND USHERING IN A
SIGNIFICANTLY DRIER/MORE STABLE AIRMASS. MOISTURE RETURN/WAA REGIME
MAY NOT RETURN TO THE AREA BY TUESDAY...WHICH WOULD MAKE CURRENT
POPS IN THE SUNDAY THROUGH MONDAY TIMEFRAME WAY TOO HIGH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 134 AM EDT WED MAY 27 2015

A LITTLE DRIER AIR HAD SPREAD INTO NRN INDIANA EARLY THIS MORNING
WITH TEMP/DWPT SPREADS 5-10F AND MODEST SWLY GRADIENT WINDS OVER
THE AREA AND UPSTREAM... THUS POTENTIAL FOR STRATUS/FOG SEEMS TO HAVE
DIMINISHED AND HAVE REMOVED FROM FWA TAF FOR EARLY THIS MORNING.
DIURNAL HEATING/DESTABILIZATION EXPECTED TO LEAD TO SCT SHRA/TSRA
DVLPG ALONG A CDFNT MOVG ACROSS THE AREA TODAY. ADDED VCSH TO SBN
TAF LATE THIS MORNING AND VCTS TO FWA EARLY THIS AFTN. GUSTY
WINDS AGAIN TODAY AHEAD OF THE FRONT... BECOMING LIGHT TONIGHT AS
POST FRONTAL RIDGE BUILDS IN.

&&

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

$$

SYNOPSIS...JT
SHORT TERM...AGD
LONG TERM...NG
AVIATION...JT


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