Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 021735
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
135 PM EDT TUE SEP 2 2014

.SYNOPSIS...
ISSUED AT 1051 AM EDT TUE SEP 2 2014

ISOLATED SHOWERS WILL CONTINUE THROUGH EARLY AFTERNOON BEFORE
DIMINISHING AS HIGH PRESSURE SETTLES OVER THE REGION. CLOUD COVER
WILL ALSO DIMINISH THROUGH THE AFTERNOON...ALLOWING HIGH
TEMPERATURES TO CLIMB INTO THE UPPER 70S AND LOW 80S. EXPECT A
QUIET NIGHT...WITH MOSTLY CLEAR SKIES AND LOWS IN THE 50S. AREAS
OF FOG WILL DEVELOP TOWARDS WEDNESDAY MORNING...BECOMING LOCALLY
DENSE AT TIMES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM EDT TUE SEP 2 2014

WOEFULLY DISHEARTENED BY POORLY MISHANDLED FINER RES MODEL OUTPUT
WITH RESPECT TO SPASTIC PRIMARY/DERIVED FIELDS THIS AM. NAM12 TOO
MOIST IN BOUNDARY LAYER AND LATER AFTERNOON INSTABILITY AND
HRRR3KM EGREGIOUSLY OVERLY ASSERTS MINOR MID LEVEL CONVERGENCE
WITH HEAVY AMOUNTS IN A STRIPE ACROSS NWRN/NRN CWA THIS AM.
FOLLOWING LESS NOISY/CONCEPTUALLY FAVORED SREF/GFS THROUGH NEAR
TERM. ZONE OF MARKED 7-5H QG FGEN OVER WCNTL MI INTO NERN IL TO
RACE ENEWD INTO MI THUMB/SWRN ONT BY ABOUT 15 UTC. ANTICIPATE
LITTLE MORE THAN LIGHT SHRA GIVEN LEADING EDGE 850-700MB MOISTURE
FLUX DIVERGENCE ASSOCIATED WITH DRYING SUB ALTOCU DECK LAYER.
MEANWHILE TO SOUTH...CONVECTIVE COMPLEX ASSOCIATED WITH WELL
VEERED 925-8H JETLET NEAR SWRN IN/NCNTL KY ON ORDER OF 45-50KTS.
WELL VEERED JET FOCUS THROUGH REMAINDER OF AM HOURS TO KEEP HEAVY
RAFL WELL SOUTH OF CWA...WITH NORTHERN EDGE /PRIMARILY STRATIFORM
QUALITY RAINSHIELD PASSING THROUGH SRN/SERN CWA WITH STRONG POP
GRADIENT. GIVEN ML CAPE 250 J/KG ISOPLETH TO REMAIN ALONG/SOUTH
OF INTERSTATE 70 WAS TEMPTED TO REMOVE TSRA ALTOGETHER...HOWEVER
MAINTAINED A TOKEN ISOLD/SLIGHT CHANCE MENTION FAR S/SERN CWA
THROUGH 12 UTC PRIMARILY FOR PSBL ANVIL/PERIPHERAL MCS STRIKE.
OTHERWISE...GRADUAL INFILTRATION OF DRIER AIR AND PROGRESSION OF
LONGWAVE TROF LEAVES LITTLE IMPETUS FOR AFTERNOON CONVECTIVE
DEVELOPMENT AND SIDED DRY/BECOMING MOSTLY SUNNY. AMPLE LONGWAVE
RADIATIONAL COOLING CONDITIONS BY SUNSET AS CENTRAL PLAINS
SURFACE RIDGING EDGES EASTWARD INTO SOUTHWEST GREAT LAKES/MID MS
VLY. GIVEN CLEAR/MCLEAR SKIES AND 925 MB THERMAL TROF POSITIONING
FROM LAKE HURON SW INTO EASTERN THIRD CWA BY DAYBREAK...HAVE
FAVORED ONGOING COOL TEMPS/CLOSER TO MAV GUID. WITH STRONG
SURFACE BASED INVERSION ANTICIPATE POSSIBLE FG
ISSUE...UNCERTAINTY OF COVERAGE...THOUGH WITH WETTING ACROSS
SOUTHERN CWA THIS AM...HAVE OPTED TO INTRODUCE AS AREAS OF FOG
FOR NOW...ALLOWING LATER SHIFTS TO EVALUATE PROBABILITY OF DENSE
NATURE.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 405 AM EDT TUE SEP 2 2014

WEAK SFC HIGH PRESSURE CENTER WILL WORK SLOWLY ESE TOWARD THE
EASTERN OH VALLEY ON WEDNESDAY PROVIDING THE AREA WITH DRY/FAIR
WX AND HIGHS INTO THE LOW-MID 80S GIVEN AMPLE INSOLATION AND 850
MB TEMPS NEAR 15C. NORTHERN STREAM WILL REMAIN ACTIVE/PROGRESSIVE
THROUGH THE REMAINDER OF THE PERIOD AS NEXT MID LEVEL TROUGH AXIS
(SOON TO DROP INTO THE PAC NW) PROPAGATES ENE ALONG THE US/CANADA
BORDER LATE THIS WEEK. THETA-E/WARM FRONT SURGE IN RESPONSE TO
ATTENDANT CENTRAL PLAINS TO UPPER MIDWEST SFC TROUGH DEVELOPMENT
BRINGS CONVECTIVE CHANCES INTO QUESTION BY LATER WEDNESDAY
NIGHT/THURSDAY MORNING. WITH THAT SAID CONTINUED WITH INHERITED
DRY/10 POP FCST IN LIGHT OF CONSISTENT ECMWF DRY SIGNAL WITH MORE
PRONOUNCED MOISTURE CONVERGENCE SETTING UP NORTHWEST OF THE FA ON
NOSE OF LLJ. THURSDAY AFTN/NIGHT SHOULD FEATURE MAINLY
DRY/HOT/HUMID CONDITIONS WITH CAPPED WARM SECTOR BECOMING FIRMLY
ESTABLISHED. DEPENDING ON CLOUD/CONVECTIVE TRENDS TEMPS MAY MAKE
A RUN AT 90F THURSDAY IN THE WEST AS SW FLOW DEEPENS AND 850 MB
TEMPS INCREASE TO 20-21C.

MODELS REMAIN IN GOOD AGREEMENT IN SAGGING A TRAILING/WEAKENING
COLD FRONT INTO A MOIST/UNSTABLE ENVIRONMENT FRIDAY-FRIDAY EVE.
CONTINUED TO UNDERCUT LIKELY CONSENSUS BLEND POPS FOR STORMS
GIVEN WEAK MID LEVEL FORCING/LAPSE RATES IN PART TO NORTHERLY
TRACK OF MAIN PV ANOMALY THRU ONTARIO. LOCALLY HEAVY RAINFALL
WILL BE POSSIBLE IF CONVECTION FIRES GIVEN HIGH MOISTURE
CONTENT/POOLING...WITH NOT MUCH OF A SEVERE RISK GIVEN POST-
FRONTAL LAG OF STRONGER MID LVL FLOW. OTHERWISE...THIS WEEKEND
INTO EARLY NEXT WEEK WILL BE CHARACTERIZED BY DRY (EXCEPT FOR
VERY LOW SHOWER CHC SOUTHEAST SATURDAY IF SLOWER FRONTAL PASSAGE
COMES TO FRUITION) AND MUCH COOLER WEATHER IN RESPONSE TO
BUILDING HIGH PRESSURE IN WAKE OF COLD FRONT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 128 PM EDT TUE SEP 2 2014

DIFFUSE FRONTAL BOUNDARY PUSHING SOUTH THROUGH THE AREA AND UPPER
LEVEL SUPPORT SHIFTING NORTHEAST OF THE REGION THIS AFTERNOON
SHOULD YIELD IMPROVING CONDITIONS AT TERMINALS THROUGH THE FIRST
HALF OF THE TAF PD. LINGERING LOW LEVEL STRATUS SLOW TO MIX OUT
THROUGH MIDDAY...ESPECIALLY INVOF KFWA. BUT RECENT SATELLITE
TRENDS SUGGEST RAPID MIXING AND LIFTING/CLEARING OF ANY MVFR CIGS
THIS AFTERNOON. RIDGING BUILDS IN OVERNIGHT WITH CALMING WINDS AND
CLEARING SKIES. LEFT PREVIOUS FCST IN TACT WITH POTENTIAL FOR
MVFR/IFR FOG TOWARD DAYBREAK WEDNESDAY MORNING.

&&

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

$$

SYNOPSIS...MCD
SHORT TERM...MURPHY
LONG TERM...STEINWEDEL
AVIATION...NG


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