Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 191419
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1019 AM EDT TUE AUG 19 2014

.SYNOPSIS...
ISSUED AT 548 AM EDT TUE AUG 19 2014

LOW PRESSURE AREA AND A SLOW MOVING COLD FRONT WILL APPROACH THE
REGION TODAY CAUSING SHOWERS AND THUNDERSTORMS TO INCREASE THIS
AFTERNOON. SEVERE STORMS ARE POSSIBLE WITH DAMAGING WINDS AND
LARGE HAIL THIS AFTERNOON. STORMS WILL BE CAPABLE OF LOCALLY
HEAVY RAIN. HIGHS TODAY WILL BE IN THE LOWER TO MID 80S. LOWS
TONIGHT WILL BE AROUND 65.

&&

.UPDATE...
ISSUED AT 1001 AM EDT TUE AUG 19 2014

REMANANTS OF MORNING MCS HAVE DISSIPATED/MOVED GENERALLY
EAST/NORTHEAST OF FORECAST AREA THIS MORNING...ALTHOUGH SCT
SHRA/TSRA WILL AFFECT NORTHERN HILLSDALE COUNTY MI THROUGH THE
REMAINDER OF THE MORNING. ADDITIONAL SCT SHOWERS AND THUNDERSTORMS
MAY DEVELOP ACROSS NORTHEAST PORTIONS OF THE AREA THROUGH MID
AFTERNOON WITH WEAK TRAILING CONVECTIVELY EHNACED VORT MAX SLOW TO
EXIT THE AREA. ATTENTION WILL SHIFT UPSTREAM THIS AFTERNOON WITH A
PAIR OF UPPER VORTICES BEING MONITORED. THE FIRST OF THESE VORTS
ACROSS NORTHERN MISSOURI ALSO APPEARS TO BE GETTING SOME
CONVECTIVE REINFORCEMENT AND SHOULD SHIFT INTO WEST CENTRAL
INDIANA THIS AFTERNOON. SECOND VORT IS ROUNDING PARENT UPPER LOW
CENTERED ACROSS THE NORTHERN GREAT LAEKS THIS MORNING AND SHOULD
BEGIN TO MOVE INTO CENTRAL/NORTHERN LOWER MI BY THIS EVENING.
CURRENT EXPECTATION IS THAT STRONGER FORCING WITH THIS SECOND VORT
MAY BE MORE DELAYED IN NATURE AND REALLY NOT AFFECT AREA UNTIL
THIS EVENING WITH FOCUS MORE LIKELY ON SOUTHERN VORT AND CONTINUAL
CONVECTIVE EHANCEMENT OF THIS SHORT WAVE AS IT REACHES LOCAL AREA
THIS AFTERNOON.

SOME QUESTIONS REMAIN AS TO MAGNITUDE OF INSTABILITY THIS
AFTERNOON WITH THE POSSIBILITY OF SOME HIGH CLOUDS OVERSPREADING
AREA OVER NEXT SEVERAL HOURS. STILL EXPECTING SBCAPES ON THE ORDER
OF 1500-2500 J/KG...ALTHOUGH SHEAR PROFILES STILL APPEAR TO BE
QUITE MARGINAL IN NATURE. SEVERE POTENTIAL STILL APPEARS TO BE
SOMEWHAT ISOLATED IN NATURE BUT WILL HAVE TO MONITOR THE
POSSIBILITY OF ANY CONVECTIVELY ENHNACED VORT MAX ALLOWING FOR
SMALLER SCALE REGIONS OF ENHANCED SHEAR THAT COULD PROMOTE BETTER
STORM ORGANIZATION. WILL CARRY POPS INTO THIS EVENING WITH
SECONDARY VORT MAX POSSIBLY ALLOWING ADDITIONAL SCT TSRA
DEVELOPMENT ACROSS NORTHWEST HALF OF THE AREA PAST PEAK HEATING
HOURS. UPDATED FORECAST SENT TO REFINE MORNING POPS...BUT NO
SIGNIFICANT CHANGES MADE AT THIS TIME.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM EDT TUE AUG 19 2014

THE EARLY MORNING SETUP FOR FOG IS FAVORABLE AGAIN WITH CLEAR
SKIES...LIGHT WINDS AND PLENTY OF LOW LEVEL MOISTURE. UPSTREAM
CLOUDS WILL ARRIVE TOO LATE TO HAVE MUCH OF AN EFFECT SO HAVE ADDED
AREAS OF FOG OVER FAR WEST AREAS EARLY THIS MORNING. THE FOGGY
CONDITIONS WILL IMPROVE EARLY THIS MORNING AS LOW LEVEL FLOW
INCREASES AND THE FOG MIXES OUT WITH DAYTIME HEATING. AN UPPER LEVEL
LOW AND ASSOCIATED TROF WILL MOVE INTO THE UPPER MIDWEST TODAY...AND
PROVIDE A MORE FAVORABLE ENVIRONMENT FOR THUNDERSTORMS OVER THE
FORECAST AREA. FAVOR THE 4KM NAM/WRF THAT APPEARS TO HAVE THE BEST
HANDLE ON THE DEVELOPMENT OF CONVECTION EARLY THIS MORNING...AND THE
REDEVELOPMENT OF STORMS LATER TODAY ALONG THE EARLIER OUTFLOW
BOUNDARY. HAVE MADE SUBSTANTIAL CHANGES TO THE GRIDS/FORECAST IN
THIS REGARD. AFTERNOON CAPE VALUES SHOULD APPROACH 3000 J/KG...AND
BRING THE POTENTIAL FOR SEVERE STORMS AS LOW TO MID LEVEL FLOW
INCREASES AND BETTER SUPPORTS THE DEVELOPMENT FOR SEVERE STORMS.
RAISED HIGHS A LITTLE TODAY. FAVOR THE WARMER GFS/MAV AS
TEMPERATURES WILL BE STARTING OUT WELL INTO THE 60S WITH 850 MB
TEMPS AROUND 18C.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 415 AM EDT TUE AUG 19 2014

DECENT MODEL AGREEMENT NOTED ALOFT THIS PD ESP W/EXPANDING UPR RIDGE
CNTRD OVR THE LWR MS VALLEY. HWVR DETAILS W/NRN CONUS FLW REMAIN A
CONVOLUTED MESS. REGARDLESS SYNOPTIC PATTN OF EXPANDING UPR RIDGE
SEWD OF PROGRESSIVE NRN STREAM FLW THROUGH SRN CANADA WILL ALLOW SFC
FNTL ZONE TO BUCK BACK NWD INTO THE NRN LAKES THIS WEEKEND.

START OF PD ON WED XPCD TO BE TRANQUIL IN WAKE OF EWD WKNG UPR LOW
ACRS THE NRN LAKES. WILL HOLD W/A TOKEN LOW CHC POP ACRS NE CWA WED
AFTN IN SPIRIT OF COLLABORATION BUT LL DRYING AND BURGEONING HGT
RISES ALOFT SHLD QUELL ANY SHOWER DVLPMNT. EWD FOLD OF UPR RIDGE WED
NIGHT AND ASSOCD EWD ADVTN OF LL THETA-E RIDGE OUT OF THE PLAINS
WILL LIKELY YIELD SOME STORMS AFT MIDNIGHT FAR SWRN ZONES AND BUMPED
PRIOR POPS THERE WHILE HOLDING W/LOW TO SLGT CHC MENTION ELSEWHERE.
SOME OF THIS MAY BLEED OVR INTO THU AM AS SFC BNDRY MIXES BACK NWD
THROUGH THE CWA. NOT PARTICULARLY IMPRESSED W/PRECIP CHCS OWING TO
BOTH LG SCALE HGT RISES ALOFT AND GENERAL CAPPING DVLPG UNDERNEATH
WARM LYR ALOFT.

ADDNL WARMING ALOFT XPCD ON FRI-SUN AS UPR RIDGE BLDS FURTHER. NO DOUBT
SIG MID LVL CAPPING LIKELY AND W/GENERAL CONSENSUS INDICATING WK
MASS FLUX ACRS THE SRN LAKES WILL CUT PRIOR EXISTING MENTIONABLE
POPS ACRS THE BOARD. OTRWS WARMEST AIR OF THE SUMMER XPCD THIS
WEEKEND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 548 AM EDT TUE AUG 19 2014

AN UPPER LEVEL LOW AND ASSOCIATED TROF WILL MOVE INTO THE UPPER
MIDWEST TODAY...AND PROVIDE A MORE FAVORABLE ENVIRONMENT FOR
THUNDERSTORMS OVER THE FORECAST AREA. BEFORE THIS...LIGHT
RADIATION FOG HAD DEVELOPED OVER NORTHERN INDIANA. THE FOG WILL
LIFT EARLY THIS MORNING AS THE LOW LEVEL FLOW INCREASES AND AS
THE FOG MIXES OUT WITH DAYTIME HEATING. ADDED TEMPO THUNDER TO THE
SBN TAF GIVEN THE OLD OUTFLOW BOUNDARY SHOULD BE IN THE AREA EARLY
THIS AFTERNOON.


&&

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

$$

UPDATE...MARSILI
SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...T
AVIATION...SKIPPER


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