Area Forecast Discussion
Issued by NWS Northern Indiana

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KIWX 291503
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1103 AM EDT FRI AUG 29 2014

.SYNOPSIS...
ISSUED AT 509 AM EDT FRI AUG 29 2014

A WARM FRONT WILL LIFT NORTHEAST INTO THE AREA TODAY INTO THIS
EVENING BRINGING INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY LATER THIS AFTERNOON AND EVENING ACROSS
NORTHWEST INDIANA AND SOUTHWEST LOWER MICHIGAN. HIGHS THIS
AFTERNOON WILL REACH THE LOWER TO MID 80S. SATURDAY WILL FEATURE
BETTER CHANCES FOR THUNDERSTORMS AND LOCALLY HEAVY RAINFALL AS A
LOW PRESSURE SYSTEM TRACKS INTO THE GREAT LAKES REGION.

&&

.UPDATE...
ISSUED AT 1052 AM EDT FRI AUG 29 2014

RAPID DESTABILIZATION ONGOING SOUTH OF WMFNTL BNDRY POSITIONED FM
CNTRL IL ESEWD THROUGH SRN IN AND AIDING RECENT NWD DVLPMNT OF
SHRA/EMBEDDED THUNDER ALG A KAAA TO KIND LINE LATE THIS MORNING.
GIVEN SAT DEPICTION OF LARGE ACCAS PLUME IN THIS SAME AREA XPC
ADDNL DVLPMNT COMMENSURATE W/CONTD SWD DESTABILIZATION AND EWD
OVERSPREAD OF LLJ CORE CURRENTLY ALIGNED THROUGH CNTRL IL. THUS
WILL LIKELY NEED TO EXPAND POPS EWD A BIT MORE AND NOTABLY ADJUST
WRN AREAS HIGHER. OTRWS LL MSTR FLUX IS CONSIDERABLE W/345K NOTED
ON H85 SFC AND MAY SEE SOME LOCALIZED HEAVY RAIN DVLP IN NW AREAS
AFT 18Z. WILL CONT TO MONITOR BUT EARLY AFTN UPDATES FORTHCOMING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT FRI AUG 29 2014

A CENTRAL PLAINS SHORTWAVE WILL OPEN NORTHEAST INTO IA/SRN MN/WI
BY LATER TODAY-TONIGHT. SOUTHWEST FLOW RAMP UP IN ADVANCE OF
ATTENDANT WEAK SFC REFLECTION/TROUGH SHOULD SUPPORT NE MIX OF SFC
WARM FRONT/INSTABILITY GRADIENT INTO MAINLY IN/MI ZONES BY LATER
TODAY-TONIGHT. MAY SEE A FEW LIGHT SHOWERS/SPRINKLES ASSOCIATED
WITH LEADING WAA ARM CLIP OUR NW IN/SW LOWER MI COUNTIES THIS
MORNING. KEPT POPS LOW (15-25%) AS MORE FOCUSED MOISTURE
CONVERGENCE TAKES PLACE WELL NNW OF THE LOCAL AREA.
STABLE/SUBSIDENT AIRMASS ON WNW PERIPHERY OF LOW-MID LEVEL RIDGE
SHOULD KEEP MOST LOCATIONS DRY FOR MOST OF THE DAY
OTHERWISE...WITH BKN MID-HIGH CLOUD CANOPY AND SE LOW LEVEL
TRAJECTORIES LIKELY KEEPING HIGHS IN CHECK (UPPER 70S TO MID
80S).

CHANCES FOR SCATTERED CONVECTION WILL INCREASE MID AFTERNOON INTO
EARLY EVENING MAINLY WEST OF THE INTERSTATE 69 CORRIDOR AS HEIGHT
FALLS BEGIN TO OVERSPREAD WARM FRONT AND WHAT SHOULD BE A
MODERATELY UNSTABLE ENVIRONMENT ALONG IT. TORRENTIAL
DOWNPOURS/LIGHTNING WILL BE THE PRIMARY CONCERNS AS PWATS
APPROACH 2". CONVECTIVE COVERAGE/CHANCES DIMINISH TONIGHT BEHIND
PRIMARY THETA-E SURGE...WITH MOISTURE CHANNEL/SFC TROUGH
ASSOCIATED WITH AFOREMENTIONED MID LEVEL WAVE REMAINING WEST OF
THE LOCAL AREA THROUGH 12Z SAT.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 509 AM EDT FRI AUG 29 2014

RELUCTANT TO MAKE SIG CHANGES IN LIGHT OF MISSED KILX 00UTC RAOB AND
NAM SPACICITY WRT PWAT/FGEN/DIV FIELDS...INSTEAD FAVORING
CONSISTENCY WITH STRONG NOD TO A CONCEPTUAL FOCUSED FCST. DEEP GOMEX
FEED WITH MONSOONAL TAP AS WESTERN KS VORTEX LIFTS/OPENS NEWD INTO
WESTERN GREAT LAKES BY SATURDAY. THIS SHOULD AFFORD WIDE PWAT STREAM
OF NEAR 2 INCHES FROM OZARKS NEWD THROUGH CWA INTO MI THUMB.
SOUTHEAST PERIPHERY OF MID TROPOSPHERIC HEIGHT FALL CENTROID STILL
AFFORDS 20-40M/12 HR TO CWA. RICH THETA-E PLUME AFFORDING TALL/THIN
CAPE PROFILES AMID DEEP PARALLEL FLOW PROFILE WITH MBE VELOCITIES
TYPICALLY AOB 8 KTS STILL RAISES FLAG FOR HEAVY RAFL POTENTIAL
SAT/SAT NIGHT DESPITE MEAGER MID RANGE MODEL SOLUTIONS/QPF.
FAVORABLE JET DYNAMICS WITH LLJ FEATURE TO TRACK UP OHIO RIVER
VALLEY SAT NIGHT MAY ALSO FACTOR INTO MCS MAINTENANCE AS WELL.
ADDITIONAL INJECTION OF OVERTAKING NORTHERN STREAM PRESENTLY MOVING
EASTWARD THROUGH NERN MT MAY ALSO FOSTER REGENERATIVE CONVECTION.
POTENTIAL FOR HEAVY RAINFALL/FLOODING/REPETITIVE TRACK COMPLEXES
REMAINS A CONCERN...ALBEIT QUITE NEBULOUS IN ANY SPATIAL/TEMPORAL
DETAIL AND ANY FURTHER STRESS THAN HWO/HVY RAFL MENTION WOULD BE
PREMATURE. REMOVED POPS SUNDAY NIGHT WITH FRONTAL BOUNDARY
STALL/LYSIS AND SHORTWAVE RIDGING LENDING NO APPRECIABLE FOCUS.
REMAINING CONCERN LIES WITH MONDAY AS SEVERE WX POTENTIAL APPEARING
LESS ATTRACTIVE WITH NEXT SHORTWAVE LIFTOUT THROUGH BROAD WRN
CANADA/NORTHERN PLAINS TROUGH. ENERGY LIFTS WELL NW OF CWA IN LIGHT
OF DEEP NEGATIVE TROF AXIS TILTING IN DEFERENCE TO DOWNSTREAM
RIDGING FOSTERED BY STRENGTH OF SERN STATES SUBTROPICAL RIDGE. WILL
SIDE WITH CONSISTENCY BUT FOCUS HIEST POPS NWRN CWA WITH GREATER
GRADIENT TO MID RANGE CHANCE POPS EAST. BY TUESDAY EVE EXPECT
FRONTAL BOUNDARY TO LAY OUT INTO OHIO VALLEY AND BEST KINEMATICS
RACING WELL NEWD INTO ONT/QUE AND AGAIN SIDE WITH NO SENSIBLE WX FOR
REMAINDER OF FCST. GRADUAL MODERATING TEMPERATURE TREND STARTING MID
WEEK AMID GRADUAL HEIGHT REBOUND SURFACE/ALOFT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 543 AM EDT FRI AUG 29 2014

MAINLY VFR THROUGH THE TAF CYCLE. HIGH BASED/VFR ISO
SHOWERS/SPRINKLES WILL BE POSSIBLE EARLY THIS MORNING AT KSBN AS
INITIAL 850 MB THETA-E PUSH LIFT THROUGH. DRIER LOW LEVEL
ENVIRONMENT FARTHER REMOVED FROM WEAK LLJ SUPPORT SHOULD HELP KEEP
KFWA MAINLY DRY THROUGH AT LEAST MID AFTN. SHORTWAVE OPENING
NORTHEAST TOWARD IA/SRN MN WILL ALLOW PRIMARY SFC WARM
FRONT/INSTABILITY GRADIENT TO MIX NORTH INTO NORTHERN INDIANA
LATER THIS AFTERNOON-EVENING. THIS FEATURE WILL BRING INCREASING
CHANCES FOR SHOWERS/STORMS WITH IT...ALTHOUGH CONFIDENCE/COVERAGE
REMAINS TOO LOW FOR ANY POINT MENTION AT THIS FCST RANGE.


&&

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

$$

UPDATE...T
SYNOPSIS...STEINWEDEL
SHORT TERM...STEINWEDEL
LONG TERM...MURPHY
AVIATION...STEINWEDEL


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.