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 250519
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
119 AM EDT WED MAR 25 2015

.SYNOPSIS...
ISSUED AT 436 PM EDT TUE MAR 24 2015

A LOW PRESSURE SYSTEM WILL TRACK INTO THE REGION LATE TONIGHT
INTO WEDNESDAY MORNING...BRINGING RAIN AND POSSIBLY A FEW
THUNDERSTORMS TO THE AREA. LOWS TONIGHT WILL RANGE FROM THE UPPER
20S OVER NORTHEAST PORTIONS OF THE AREA TO THE UPPER 30S
SOUTHWEST...THOUGH TEMPERATURES ARE EXPECTED TO RISE INTO THE 40S
OVER THE ENTIRE AREA BY WEDNESDAY MORNING. BECAUSE OF THE
INITIALLY COLDER TEMPERATURES...THERE IS A CHANCE OF FREEZING RAIN
IN THE NORTHEAST. AS TEMPERATURES WARM OVERNIGHT...ANY FREEZING
RAIN SHOULD TRANSITION TO RAIN. NO ICE ACCUMULATION IS EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 328 PM EDT TUE MAR 24 2015

COOL/DRY LOW LEVEL EASTERLY FLOW ON THE SW PERIPHERY OF AN EASTERN
LAKES SFC ANTICYCLONE WILL GIVE WAY TO A PERIOD OF RAIN OVERNIGHT.
THIS WILL OCCUR AS A VIGOROUS MID LEVEL SHORTWAVE (NOW ADVANCING
THROUGH KANSAS PER AFTERNOON WATER VAPOR) RACES TOWARD THE LOWER
GREAT LAKES WHILE TAKING ON A NEGATIVE TILT. INITIAL SURGE OF
850-700 MB THETA-E ADVECTION WILL BRING INCREASING CLOUDS AND
CHANCES FOR SHOWERS INTO WESTERN PORTIONS OF THE FA THIS
EVENING...ALTHOUGH HELD POPS IN LOW-MID CHC CATEGORY GIVEN FIGHT
WITH ANTECEDENT DRY AIRMASS. DEEP UVM PLUME ASSOCIATED WITH THE
DYNAMIC SHORTWAVE AND EXCELLENT MOISTURE TRANSPORT (850 MB
DEWPOINT SURGE TO 5-6C) WITHIN A 50-60KT LLJ WILL ALLOW MORE
WIDESPREAD/HEAVIER PCPN TO PIVOT NE THROUGH THE LOCAL AREA BTW
06-12Z. A FEW RUMBLES OF THUNDER ALSO REMAIN POSSIBLE GIVEN STRONG
FORCING AND STEEPENING MID LEVEL LAPSE RATES. PCPN MAY BEGIN AS A
BRIEF PERIOD OF -FZRA NORTHERN/EASTERN ZONES OVERNIGHT BEFORE
WAA/LATENT HEATING QUICKLY OVERWHELMS THE NEAR SURFACE
LAYER/INVERSION...BUT NOT EXPECTING ANY ICE ACCUMULATIONS/IMPACTS
ATTM. OTHERWISE...TEMPS MAY DROP A FEW DEGREES EARLY THIS EVENING
BEFORE STEADILY RISING OVERNIGHT.

MID LEVEL SUBSIDENCE/DRYING WILL OVERSPREAD THE AREA ON WEDNESDAY IN
THE WAKE OF THIS UPPER WAVE...WITH LINGERING SHOWERS/DRIZZLE
POSSIBLE EARLY IN THE MORNING ALONG THE SFC OCCLUSION. TEMPS WILL BE
NOTICEABLE MILDER TOMORROW IN WAKE OF THIS FEATURE BUT JUST HOW WARM
WE GET REMAINS HIGHLY UNCERTAIN AND DEPENDENT ON HOW QUICKLY
LINGERING STRATUS HANGS ON AND WHERE TRAILING SFC BOUNDARY LAYS OUT
BY AFTERNOON. OPTED FOR A MODEL BLEND FOR NOW WHICH CAME OUT A FEW
DEGREES COOLER THAN THE PREV FCST.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 328 PM EDT TUE MAR 24 2015

TOPSY-TURVY SPRING PATTN THIS PD AS BATTLE BTWN WINTER AND SPRING
CONTS.

SECONDARY FNTL WAVE XPCD TO DVLP WED NIGHT ALG TRAILING CDFNT IN
BEHIND VIGOROUS CYCLONE LIFTING UP ACRS THE LAKES ON WED. GOOD
00-12Z AGREEMENT ON PLACEMENT OF BNDRY TO NR/ALG OH RVR AND XPC BULK
OF PCPN TO LINE UP ALG NRN EDGE OF LL THETA-E RIDGE. WILL CONTRACT
GOING POP GRADIENT FURTHER ESP FAR NW TO ACCOUNT FOR LK MI NEG
THETA-E SINK. OTRWS SECONDARY NRN STREAM TROUGH AMPLIFYING SEWD ACRS
THE LAKES THU NIGHT WILL PROPEL ASSOCD ARCTIC FNT THROUGH THE REGION
W/SHARPLY COLDER TEMPS FOLLOWING IN ITS WAKE FOR FRI-SAT AS YET
ANOTHER UNSEASONABLY STG RIDGE BLDS SEWD OUT OF SRN CANADA. IN FACT
MEX/EC MOS BASED GUIDANCE IS SIMILAR W/ADVERTISE DEPARTURES OF 20-25
DEGREES BLO NORMAL.

PATTN ALOFT XPCD TO FLATTEN LT WEEKEND INTO EARLY NEXT WEEK
W/MODERATING TEMPS BACK TO NORMAL IN THE LOW-MID 50S BY DY8 (TUE).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 108 AM EDT WED MAR 25 2015

LARGE AREA OF RAIN APCHG NRN INDIANA FROM THE S-SW SHOULD OVERSPREAD
THE TERMINALS IN THE NEXT COUPLE OF HOURS. TEMPS AT KFWA STILL
BELOW FREEZING BUT LOW LEVEL WAA SHOULD CAUSE IT TO RISE ABOVE FREEZING
BY THE TIME THE RAIN BEGINS. MVFR/IFR CONDITIONS UPSTREAM WITHIN
THE RAIN AREA EXPECTED TO IMPACT THE TERMINALS THIS MORNING.
ELEVATED INSTABILITY EXPECTED TO BE ON A DECREASING TREND
EARLY THIS MORNING... SO WILL CONT TO LEAVE TS OUT OF THE TAFS...
THOUGH ISOLATED THUNDERSTORMS REMAIN PSBL IN THE AREA. RAIN SHOULD
MOVE OUT OF THE AREA AROUND 12Z BUT LOW LEVELS EXPECTED TO BE
SATURATED BY THAT TIME WITH IFR STRATUS AND SOME -DZBR PERSISTING
DURING THE MORNING HOURS. DRIER AIR AND MIXING DURING THE AFTN
SHOULD CAUSE A RETURN OF VFR CONDITIONS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

SYNOPSIS...MCD
SHORT TERM...STEINWEDEL
LONG TERM...T
AVIATION...JT


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.