Area Forecast Discussion
Issued by NWS Northern Indiana

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 171004
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
604 AM EDT FRI APR 17 2015

.SYNOPSIS...
ISSUED AT 410 AM EDT FRI APR 17 2015

HIGH PRESSURE WILL BRING DRY AND MOSTLY SUNNY CONDITIONS TODAY.
HIGHS TODAY WILL BE IN THE LOW TO MID 70S WITH LOWS TONIGHT AROUND
50 DEGREES. ANOTHER MILD DAY EXPECTED ON SATURDAY BEFORE THE NEXT
CHANCE OF RAIN ARRIVES ON SUNDAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM EDT FRI APR 17 2015

QUICK SHOT OF RADIATIONAL COOLING BEHIND EXITING CLOUD COVER HAS
ALLOWED SOME PATCHY FOG TO DEVELOP...MAINLY IN OUR FAR SOUTHERN
COUNTIES WITH DRIER CONDITIONS IN PLACE ACROSS OUR NORTHWESTERN
CWA. DRIER AIR SHOULD CONTINUE TO SLOWLY PUSH SOUTHEAST AND LATEST
OBS/AREA WEBCAMS SUGGEST DENSE FOG IS FAIRLY ISOLATED. BLUFFTON
WEBCAM IS MAINLY CLEAR AND BOTH KMCX AND KGGP HAVE BEEN RISING TO
1SM AT TIMES. GIVEN TENUOUS NATURE AND LIMITED AREAL EXTENT OF
DENSE FOG IN OUR CWA...WILL FORGO AN ADVISORY AND CONTINUE TO
HANDLE WITH SPS`S. ANY FOG THAT DOES DEVELOP WILL DISSIPATE VERY
QUICKLY AFTER SUNRISE AS DIURNAL HEATING AND MIXING COMMENCE.

MAIN FORECAST CONCERN FOR TODAY WILL BE HOW HIGH TEMPS MANAGE TO
CLIMB. CONFLUENCE ALOFT AND MIDLEVEL AVA WILL MAINTAIN A SUBSIDENT
ENVIRONMENT WITH NORTHWEST FLOW ADVECTING A DRY AIRMASS INTO THE
REGION. EXPECT MOSTLY SUNNY SKIES WITH JUST A LOW CHANCE OF SOME
CIRRUS BEING BLOWN OFF CONVECTION OVER THE CENTRAL PLAINS. DRY LOW
LEVELS AND NEARLY FULL SUN WILL ALLOW MIXING HEIGHTS TO CLIMB TO
ALMOST 800MB THIS AFTERNOON. TEMPS AT THAT LEVEL WILL BE AROUND
6C...SUGGESTING MID 70S ARE POSSIBLE. GUIDANCE HAS STRUGGLED WITH
TEMPS DURING THESE DEEP MIXING EVENTS RECENTLY AND SEVERAL MEMBERS
STILL SEEM TOO COOL. HAVE THEREFORE HELD VERY CLOSE TO INHERITED
FORECAST WHICH IS ON THE HIGH SIDE OF GUIDANCE ENVELOPE. SOME FIRE
WEATHER CONCERNS AS DEEP MIXING WILL PROBABLY ALLOW AFTERNOON
DEWPOINTS TO DROP INTO THE LOW 40S (RH VALUES AROUND 30 PERCENT).
WIND SPEEDS WILL BE NOWHERE NEAR RED FLAG CRITERIA THOUGH AND WITH
JUST MARGINAL RH VALUES IN THE FORECAST RIGHT NOW...WILL LET DAY
SHIFT MONITOR DIURNAL TRENDS FOR ANY HEIGHTENED AWARENESS MESSAGES.
QUIET WEATHER CONTINUES INTO THE OVERNIGHT. LOW DEWPOINTS...MOSTLY
CLEAR SKIES...AND LIGHT SURFACE WINDS SHOULD PROMOTE GOOD
RADIATIONAL COOLING. A BIT CONCERNED ABOUT POTENTIAL FOR A FEW
MID/UPPER LEVEL CLOUDS BASED ON NAM AND GFS FORECAST SOUNDINGS BUT
STILL PREFER TO LEAN TOWARD COOLER MOS GUIDANCE. CUT OVERNIGHT LOWS
BY A DEGREE OR TWO WITH VALUES DROPPING TO AROUND 50F.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 410 AM EDT FRI APR 17 2015

GOOD INTERMODEL AGREEMENT THIS MORNING ON UPCOMING MERGER OF NRN/SRN
STREAM ENERGY BY LT WEEKEND. POTENT SRN STREAM CLOSED LOW SPINNING
NR THE FOUR CORNERS THIS MORNING WILL WOBBLE NEWD INTO THE HIGH
PLAINS SAT BFR PHASING W/NRN STREAM SW DIGGING THROUGH THE NRN
PLAINS SUN. NET RESULT ACRS THE LAKES/OH VALLEY WILL BE A VIGOROUS
PCPN SHIELD ON SUNDAY ALG NOSE OF LL MSTR SURGE INVOF DEEPENING SFC
REFLECTION. CONSENSUS TRACK OF SFC FTR OVERHEAD WOULD HERALD SIG
PROMISE FOR A MUCH NEEDED SUBSTANTIAL RAIN EVENT.

SECONDARY PRECIP MAX LIKELY TO DVLP AHD OF DIGGING NRN STREAM SYS
ACRS THE WRN LAKES LT SUN NIGHT/MON AM HWVR EWD TRANSLATION OF
MERGED FNTL ZONE UNCERTAIN W/FAIRLY SIG SPREAD INDICATED IN 00Z
GUIDANCE. HWVR ALLBLEND SOLUTION PROVIDES FOR A DECENT MIDDLE GROUND
CONFINING HIGHER POPS EAST. NRN STREAM CYCLONE TO THEN CUTOFF OVR
THE NRN LAKES MID PD BFR SLOWLY SHIFTING EWD INTO NEW ENGLAND BY LT
WEEK.

OTRWS W/CWA NESTLED IN ALG SUBSIDENT PERIPHERY OF UPR TROUGH AXIS
TUE ONWARD...NO NEED TO CARRY ALLBLEND LOW CHC POPS THROUGH DYS 5-7.
INCREASING NWRLY FLW ALOFT AND DEEPENING CAA WEDGE XPCD THROUGH THE
WEEK W/COOLING TEMPS THROUGHOUT. ALLBLEND TEMPS LIKELY A BETTER FIT
VS PURE MOS GUIDANCE ESP LTR PDS AS GEM/ECMWF BLEND QUITE A BIT
COLDER AND POINTING TO A FROST THREAT AS EARLY AS WED AM. HWVR THIS
THREAT LIKELY THEREAFTER W/GEM/ECWMF INDICATING A HARD FREEZE PSBL
BOTH THU NIGHT AND AGAIN FRI NIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 604 AM EDT FRI APR 17 2015

SEVERAL SITES ACROSS NORTHERN INDIANA ARE REPORTING MVFR BR DUE TO
RADIATIONAL COOLING...LIGHT WINDS...AND RESIDUAL MOISTURE. DENSE
FOG IS CONFINED TO CENTRAL INDIANA. BRIEF REDUCTION TO MVFR
CATEGORY WILL BE POSSIBLE AT THE TERMINALS THROUGH 13Z. OTHERWISE
EXPECT VFR CONDITIONS TO PERSIST THROUGH THE REST OF THE PERIOD
WITH LIGHT WINDS AND HIGH PRESSURE OVERHEAD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR INZ020-022-
     023-032>034.

MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...T
AVIATION...AGD


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.