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 310552
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
152 AM EDT TUE MAR 31 2015

.SYNOPSIS...
ISSUED AT 145 AM EDT TUE MAR 31 2015

DRY WEATHER WILL RETURN TODAY AS THE CLIPPER SYSTEM...THAT
BROUGHT SOME LIGHT RAIN TO THE REGION MONDAY NIGHT INTO EARLY THIS
MORNING...MOVES TO THE MID ATLANTIC REGION. TEMPERATURES WILL BE
A BIT COOLER THAN YESTERDAY...BUT SHOULD STILL MAINLY REACH INTO
THE 50S. LOWS TONIGHT WILL DIP BACK INTO THE 30S.

&&

.UPDATE...
ISSUED AT 942 PM EDT MON MAR 30 2015

EVENING UPDATE SENT MAINLY TO ACCOUNT FOR POP TRENDS. LEAD
ISENTROPIC LIFT(FGEN)/LOW LEVEL THETAE SURGE HAS BEEN SUFFICIENT
FOR LIGHT RAIN ACROSS FAR NORTHERN INDIANA THIS EVENING DESPITE
FAIRLY DRY LOWEST 4K FT. NAM ISENTROPIC PROGS SUGGEST RISING CPDS
AFTER MIDNIGHT IN THE WAKE OF THIS LEADING ISENTROPIC LIFT/FGEN
FORCING...AND HAVE GENERALLY FOLLOWED PREVIOUS FORECAST IDEA OF
DECREASING POPS FROM SOUTHWEST TO NORTHEAST. ONLY OTHER TWEAK WAS
TO MODIFY WINDS FOR A SLIGHTLY SOUTHWARD ADJUSTED LOW TRACK BASED
ON CURRENT TRENDS...BUT OTHERWISE NO SIGNIFICANT CHANGES TO
FORECAST ELEMENTS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 340 PM EDT MON MAR 30 2015

UPPER LEVEL JET STREAK WILL TRANSITION INTO THE GREAT LAKES
TONIGHT AND SEND A STRENGTHENING MIDLEVEL VORT MAX THROUGH THE
REGION. TIGHT BAROCLINIC ZONE IS ALREADY IN PLACE OVER THE GREAT
LAKES AND THIS WAVE WILL INCITE A GOOD 850MB FRONTOGENETIC
RESPONSE...ESPECIALLY GIVEN REDUCED STABILITY ABOVE THIS LAYER.
TRACK IS NOT FAVORABLE FOR MOST OF OUR CWA THOUGH. ACTIVE FRONTAL
ZONE WILL BE DRAPED ACROSS CENTRAL MICHIGAN AND ONLY CLIPS OUR
FAR NORTHEAST COUNTIES. STILL SOME DISAGREEMENT AMONG LATEST NWP
WITH RESPECT TO EXACT TRACK AND THIS WILL HAVE A LARGE EFFECT ON
HOW MUCH OF OUR CWA SEES PRECIP GIVEN VERY SHARP CUTOFF TO FORCED
ASCENT. KEPT OVERALL SPIRIT OF PREVIOUS FORECAST BUT DID INCREASE
POPS OVER OUR NORTHEAST HALF BASED ON LATEST HI-RES GUIDANCE.
AREAS SOUTH OF US-30 MAY REMAIN COMPLETELY DRY. FORECAST
SOUNDINGS SHOW LOWEST 2 KFT IS WARM ENOUGH TO SUPPORT AN ENTIRELY
RAIN EVENT IN AREAS THAT DO SEE PRECIP. NOT IMPOSSIBLE THAT OUR
FAR NORTHEAST COULD SEE A BRIEF MIX DUE TO WET BULB EFFECTS BUT
CHANCES AND IMPACTS ARE TOO LOW FOR INCLUSION IN THE FORECAST.
RAIN SHOULD EXIT BY TOMORROW MORNING WITH DRIER AIR RETURNING TO
THE REGION.

LOWS TONIGHT WILL PROBABLY STAY ON THE WARM SIDE GIVEN INCREASING
SOUTHWEST GRADIENT WITH PASSING SURFACE LOW. NUDGED INHERITED
FORECAST UP JUST A BIT. HIGHS TOMORROW WILL BE SLIGHTLY COOLER
THAN TODAY GIVEN BRIEF RETURN TO NNW FLOW/CAA. DECENT MIXING
DEPTHS UNDER INCREASING SUN WILL AT LEAST PARTIALLY OFFSET CAA
THOUGH AND HIGHS IN OUR SOUTHWEST COULD STILL REACH THE UPPER
50S.


&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 PM EDT MON MAR 30 2015

TRANSITION TO A MORE BONA-FIDE SPRING PATTN XPCD THIS PD W/LONGER
TERM SUGGESTIONS OF GENERAL WKNG OF NEG HGT ANOMALIES UP ACRS ERN
CANADA AND MORE TROUGHING ACRS THE WRN US BOTH OF WHICH HAVE BEEN
LAGGING FOR SVRL MONTHS.

BEGINNING OF PD LOOKS STELLAR W/SIG LL THERMAL MODERATION AHD OF
POTENT NRN STREAM SW SWEEPING THROUGH SRN CANADA. SWWD TRAILING
FNTL BNDRY ASSOCD/W THIS SYS LOOKS ACTIVE THU AFTN TIMED W/NWD
REACH OF LL GOMEX MSTR RTN AND PERHAPS SOME RISK FOR THUNDER.
HWVR WILL AWAIT LTR GUIDANCE AS FNTL TIMING MAY BE POOR W/LIMITED
SFC BASED DESTABILIZATION AND EXTENT OF NWD MOISTENING.

TAIL END OF UPR LVL DISTURBANCE EJECTS EWD FRI W/SFC WAVE XPCD TO
DVLP INVOF THE OH RVR VALLEY. NWD REACH OF POTENTIAL OVERRUNNING
PCPN SHIELD ASSOCD/W THIS SYS STILL QUITE UNCERTAIN AND KEPT
W/SUBDUED N-S POP GRADIENT.

UNSETTLED PATTN LOOKS TO INCREASE THROUGH NXT WEEK W/TEMPS
MODERATING TO AOA NORMAL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 153 AM EDT TUE MAR 31 2015

VEERING LOW LEVEL JET NOW TRAVERSING NRN IN. GAVE SOME GREATER
DETAIL WITH RESPECT TO SHIFTING 2KFT FLOW NEXT FEW HOURS. STILL
SOME CONCERN WITH WINDOW OF HIGH END MVFR CIGS...SPCLY AT KSBN
WITH ONSET OF CU FIELD GENERATION LATER THIS AM. HOWEVER...GIVEN
QUITE LOW POTNL FOR SIGNIFICANCE/BLO 2KFT CIG HGHTS...WILL DEFER
TO LATER HIER RES GUID FOR 12 UTC ISSUANCE.

&&

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

$$

UPDATE...MARSILI
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...T
AVIATION...MURPHY


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.