Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 150205 CCA
AFDIWX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NORTHERN INDIANA
820 PM EDT MON APR 14 2014

.SYNOPSIS...
ISSUED AT 318 PM EDT MON APR 14 2014

GUSTY WINDS AND COLD TEMPERATURES WILL PERSIST THROUGH WEDNESDAY MORNING.
AN UPPER LEVEL DISTURBANCE WILL BRING ANOTHER ROUND OF
PRECIPITATION TO THE REGION TONIGHT. PRECIPITATION WILL LIKELY
BEGIN AS A MIXTURE OF RAIN AND SNOW BEFORE CHANGING OVER TO ALL
SNOW. SOME LIGHT SNOW ACCUMULATIONS WILL BE POSSIBLE ESPECIALLY
EAST OF INTERSTATE 69.

&&

.UPDATE...
ISSUED AT 756 PM EDT MON APR 14 2014

TWO DISTINCT AREAS OF FORCING NOTED THIS EVENING. THE FIRST BEING
A HIGHLY ELEVATED AXIS OF FRONTOGENESIS...BASED CLOSED TO 600 HPA
ACROSS NORTHERN ILLINOIS AND NOW APPROACHING NORTHWEST INDIANA.
UPPER VORTICITY MAX WITH ASSOCIATED UPSTREAM SHORT WAVE ACROSS
NWRN ILLINOIS IS HIGHLY SHEARED IN NATURE AND SHOULD TEND TO LIFT
NORTHEASTWARD INTO THE UPPER GREAT LAKES REGION OVERNIGHT. NAM 600
HPA F-VECTOR CONVERGENCE PROGS DO SUGGEST AXIS OF STRONGEST FGEN
FORCING GRADUALLY LIFTING NORTHEASTWARD THIS EVENING ACROSS MUCH
OF WESTERN MICHIGAN SO SOME QUESTION REMAINS AS TO HOW ORGANIZED
THIS BANDING WILL MAINTAIN ACROSS NORTH CENTRAL INDIANA. STILL
EXPECTING ACCUMULATIONS GENERALLY UP TO AN INCH...WITH THE
POSSIBILITY OF SOME SLIGHTLY HIGHER AMOUNTS...ESPECIALLY ACROSS
THE FAR NORTHWEST.

A SECOND VORT MAX LIFTING NORTHEAST OUT OF THE SOUTHERN PLAINS HAS
ALREADY ACTIVATED AREA OF RAIN ALONG STRONG MID LEVEL FRONT...AND
THIS AREA OF PRECIP WILL OVERSPREAD ESPECIALLY EASTERN HALF OF THE
FORECAST AREA LATE EVENING/OVERNIGHT. PTYPE WILL BE A CHALLENGE
INITIALLY GIVEN SFC WET BULBS JUST ABOVE FREEZING AND POTENTIAL
MAINTENANCE OF VERY WEAK ELEVATED WARM LAYER THAT COULD INTRODUCE
BRIEF PERIOD OF SLEET BEFORE CHANGEOVER TO SNOW. HAVE NOT MADE
MUCH CHANGE TO PREVIOUS FORECAST AT THIS TIME...WITH JUST SLIGHT
UPWARD ADJUSTMENT IN ACCUMULATIONS INTO THE 1 TO 3 INCH RANGE
ACROSS EXTREME SOUTHEAST PORTIONS OF THE AREA WHERE BEST CO-
LOCATION OF 700-600 HPA FGEN FORCING AND ELEVATED INSTABILITY
EXIST. GIVEN STRENGTH OF MID LEVEL FRONT/FGEN...WILL NEED TO
MONITOR TRENDS FOR ANY MESOSCALE BANDING ISSUES ACROSS THE FAR
SOUTHEAST LATE EVENING/OVERNIGHT...BUT FOR NOW WILL HOLD OFF ON
ANY HEADLINES.

WILL LIKELY BE SENDING ANOTHER EVENING UPDATE IN THE NEXT HALF
HOUR TO FURTHER INCREASE POPS ACROSS THE NORTHWEST TO ACCOUNT FOR
UPPER LEVEL FGEN FORCING...AND TO SLIGHTLY INCREASE ACCUMS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 316 PM EDT MON APR 14 2014

UNSEASONABLE COLD HAS REPLACED YDAS UNSEASONABLE WARMTH W/24HR
CHGS IN EXCESS OF 30 DEGREES COLDER. ONLY THING KEEPING RECORD
MINS IN CHECK ARE CONTD EXTENSIVE LOW CLD CVR WITHIN MOIST
CYCLONIC FLW AND SUSTAINED SFC GRADIENT. TUE NIGHT IS ANOTHER
STORY HWVR.

LTL OF NOTE NR TERM OTHER THAN DEEPENING OF CAA WEDGE WHICH DOES NOT
HIT EQUILIBRIUM UNTIL MID MORNING TOMORROW. DRYSLOT WRAPPING NEWD
UNDERNEATH EJECTING LEAD SW OVR SRN ONTARIO HAD CUTOFF EARLIER SHRA
ACTIVITY HWVR STILL MOIST ENOUGH INVOF OF 850MB FNT TO FOSTER SOME
PATCHY DZ WHICH WILL CONT TO MIGRATE EWD THIS AFTN.

SHRT TERM DILEMMA IS WHAT TO DO IF ANYTHING W/SECONDARY UPSTREAM SW
WHICH DRIVES EWD OVERNIGHT. 12Z GUIDANCE AS A WHOLE SIMILAR IN SCOPE
ALOFT W/PRIOR GUIDANCE YET CERTAINLY DRIER WEST AND CENTRAL THIS
EVENING. CURRENT OBSERVATIONS UPSTREAM OFFER NO PANACEA EITHER
W/GENERALLY FRACTURED/THIN BAND OF GENERALLY LIGHT SNOW OR FLURRIES
FM ERN IA SWWD INTO SE KS. HWVR AREA OF ELEVATED CONVN BREAKING OUT
ACRS SWRN AR SOMETHING SVRL HIGHRES SOLUTIONS ARE KEYING IN ON AND
SUGGEST GENERAL NEWD CONSOLIDATION/EXPANSION THIS EVENING INTO ERN
ZONES. CONSENSUS QPF AXIS ALG/E OF A PORTLAND...DEFIANCE...WAUSEON
LINE SUGGEST SOME IMPACT PROBABLE LT THIS EVENING AND OVERNIGHT.
HWVR SFC TEMP AND UPSTREAM PCPN SHIELD UNCERTAINTIES PRECLUDE MAKING
ANY WWA HIGHLITE DECISIONS AT THIS POINT AND WILL DEFER TO EVENING
SHIFT TO SEE HOW IT UNFOLDS UPSTREAM.

OTRWS DEEP LYRD SUBSIDENT DRYING FOLLOWS ON TUES W/SKIES CLRG. HWVR
ANOMALOUSLY COLD LL THERMAL TROUGH LINGERS THROUGH AFTN BFR BREAKING
DOWN AND EVEN W/INSOLATION SFC TEMPS WILL STRUGGLE INTO THE 30S.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 316 PM EDT MON APR 14 2014

NEAR RECORD/RECORD COLD NIGHT IN STORE TO START THE PERIOD AS LAST
OF THE COLD AIR BEGINS TO SHIFT EAST BUT NOT BEFORE SENDING LOWS
INTO THE LOWER 20S OR POSSIBLY A TOUCH COOLER IN SPOTS. WHILE
CLIMATOLOGICALLY FROST/FREEZE THIS FAR NORTH ISN`T NORMALLY AN
ISSUE...SOME BUDDING OF FRUIT BEARING TREES MAY BE UNDERWAY. WITH
LOWS THIS COLD...SOME POTENTIAL FOR IMPACTS. SOMETHING TO BE
MONITORED OVER THE NEXT 12 TO 24 HOURS.

LOW PRESSURE WILL MOVE OUT OF THE CENTRAL PLAINS TOWARDS THE GREAT
LAKES. BUILDING UPPER LEVEL HGTS WILL HELP STEER THIS FEATURE WELL
NORTH OF THE AREA BUT WILL DRAG A FRONTAL BOUNDARY INTO THE REGION
THAT WILL STALL OUT. ANOTHER PIECE OF ENERGY COMING OUT OF THE SW
STATES WILL STRENGTHEN SOMEWHAT WITH SFC REFLECTION TAKING SHAPE
ACROSS KANSAS AND THEN MOVING TOWARDS THE LOWER GREAT LAKES BY
FRIDAY. WHILE NO MASSIVE WARM UPS ARE IN STORE AT THIS POINT...850
MB TEMPS WILL CLIMB TO +2 TO +4 MUCH OF THE PERIOD...ALLOWING FOR
MORE SEASONABLE TEMPS GENERALLY IN THE 55 TO 60 DEGREE RANGE. IN
TERMS OF POPS...HAVE INCREASED SOMEWHAT FOR FRI/FRI NGT BUT HOLDING
SHY OF LIKELY AS SOME TIMING DIFFERENCES STILL EXIST.

RECORD LOWS...
       16TH
SBN    22 (1935)
FWA    24 (1935)

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 756 PM EDT MON APR 14 2014

A PAIR OF SHORT WAVES WILL BRING CONTINUED PRECIP TO THE TERMINALS
TONIGHT. PRIMARILY LIGHT SNOW IS EXPECTED AT KSBN IN ASSOCIATION
WITH UPPER LEVEL FRONT TRACKING INTO THE WESTERN GREAT LAKES.
BRUNT OF THIS FORCING SHOULD SHIFT EAST OF THE TERMINAL BY 06Z.
WHILE THIS FORCING SHOULD TEND TO WEAKEN AND LIFT NORTHWARD OVER
NEXT SEVERAL HOURS...DID AMEND TO INCLUDE SOME IFR VSBYS THROUGH
04Z AT KSBN. SCT LAKE EFFECT SNOW SHOWERS ARE ALSO POSSIBLE AFTER
08Z...BUT CONFIDENCE IN OCCURRENCE IS TOO LOW FOR INCLUSION AT
THIS TIME. AN AREA OF EXPANDING RAIN ALSO WORKING NORTHWARD FROM
CENTRAL INDIANA WILL GRADUALLY MIX WITH AND THEN CHANGE TO SNOW
LATE THIS EVENING ACROSS NORTHEAST INDIANA...AND NOT MUCH CHANGE
MADE TO PREVIOUS TAFS FOR KFWA IN THIS RESPECT. HAVE INCLUDED IFR
CONDITIONS AT KFWA IN THE 05Z-08Z TIMEFRAME BEFORE STRONG MID
LEVEL FRONTOGENESIS SHIFTS EAST OF THE TERMINAL. NORTHWEST WINDS
TO CONTINUE THROUGH THE PERIOD WITH GUSTS TO AROUND 20 KNOTS ONCE
AGAIN ON TUESDAY...AND MAINLY VFR CONDITIONS DEVELOPING AS DRIER
AIR ADVECTS INTO REGION.

&&

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

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI/STEINWEDEL
SHORT TERM...T
LONG TERM...FISHER
AVIATION...MARSILI


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