Small Craft Advisory 63, NWS Northern Indiana

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
428 PM EST WED DEC 23 2015

.SYNOPSIS...
ISSUED AT 415 PM EST WED DEC 23 2015

SHOWERS AND ISOLATED THUNDERSTORMS WILL DIMINISH OVERNIGHT AS A
COLD FRONT TRACKS ACROSS THE AREA. A FEW OF THE SHOWERS AND STORMS
THIS EVENING MAY PRODUCE GUSTY WINDS AND BRIEF DOWNPOURS. VERY
WINDY CONDITIONS CAN BE EXPECTED LATE EVENING INTO THE OVERNIGHT
BEHIND THE COLD FRONT. DRY CONDITIONS ARE EXPECTED FOR THURSDAY
WITH COOLER CONDITIONS...BUT STILL WELL ABOVE NORMAL FOR LATE
DECEMBER. LOW TEMPERATURES TONIGHT WILL RANGE FROM 40 TO 45...WITH
HIGH TEMPERATURES ON THURSDAY FROM THE MID 40S TO LOWER 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 415 PM EST WED DEC 23 2015

POTENTIAL OF ISOLATED DAMAGING WIND GUSTS WITH SHOWERS/ISOLATED
THUNDERSTORMS THIS EVENING AND A BRIEF PERIOD OF STRONG
SYNOPTIC WINDS TONIGHT WILL CONTINUE TO BE THE PRIMARY FOCUS OF
THE SHORT TERM.

PREFRONTAL TROUGH AND ASSOCIATED 1.2-1.4 INCH PWAT AXIS WILL
CONTINUE EASTWARD ACROSS FAR NORTHEAST INDIANA/NORTHWEST OHIO
EARLY THIS EVENING. MAGNITUDE OF INSTABILITY HAS BEEN THE PRIMARY
LIMITING FACTOR FOR A MORE SUBSTANTIAL SEVERE THREAT TO THIS POINT
(CAPES ON THE ORDER OF 250 J/KG)...BUT BANDS/FINE LINES OF SHOWERS
POSING SOME THREAT OF 45-55 MPH GUSTS HAVE BEEN NOTED ACROSS MUCH
OF NORTH CENTRAL INDIANA THIS AFTERNOON. WHILE SHEAR VECTORS HAVE
REMAINED LARGELY PARALLEL TO THESE BANDS...CANNOT DISCOUNT SOME
SPORADIC ISOLATED DAMAGING WIND GUSTS ACROSS NORTHEAST
INDIANA/NORTHWEST OHIO OVER THE NEXT FEW HOURS AS MORE CHANNELED
LOW LEVEL FLOW SHIFTS EASTWARD IN ASSOCIATION WITH PREFRONTAL
TROUGH. A SECONDARY AREA OF CONCERN IS A CONVECTIVE COMPLEX THAT
HAS TRACKED INTO CENTRAL INDIANA FROM SOUTHERN MISSOURI THIS
AFTERNOON. THESE STORMS HAVE OUTRACED MORE SUBSTANTIAL
INSTABILITY...BUT WILL NEED TO MONITOR SOUTHEAST PORTIONS OF THE
FORECAST AREA THROUGH 00Z WITH POSSIBLE IMPACTS FROM NORTHERN
BOOKEND VORTEX.

SCATTERED THUNDERSTORMS HAVE ALSO INITIATED ACROSS NORTHEAST
MISSOURI/SOUTHEAST IOWA OVER THE PAST HOUR ASSOCIATED WITH ANOTHER
STRONG MID/UPPER LEVEL IMPULSE AND STRONGER FRONTAL CONVERGENCE.
THIS SHORT WAVE WILL LIFT NORTHEAST ACROSS THE WESTERN GREAT LAKES
TONIGHT WITH FORCING FROM THIS WAVE IMPACTING AREAS ESPECIALLY
ACROSS NORTHWEST/NORTHERN PORTIONS OF THE FORECAST AREA. LATEST
RUC DOES INDICATE A POCKET OF 500 J/KG SURFACE BASED INSTABILITY
WORKING ACROSS FAR NORTHWEST INDIANA LATER THIS EVENING AND WILL
MAINTAIN CHANCE/SCT SHOWER/STORM MENTION GOING THROUGH THE EVENING
IN ASSOCIATION WITH THIS FORCING/COLD FRONT.

THE OTHER CONCERN TONIGHT WILL BE FOR A PERIOD OF STRONG SYNOPTIC
WINDS JUST AHEAD AND BEHIND THE COLD FRONT. IMPRESSIVE
CYCLOGENESISAND PRONOUNCED PRESSURE RISE/FALL COUPLET WILL ALSO
ENHANCE WINDS IN ADDITION TO THE STEEPENING LOW LEVEL LAPSE RATES.
THE TRACK OF THE ISALLOBARIC CONTRIBUTION WOULD SEEM TO FAVOR
NORTHWEST AREAS FOR PUSHING ADVISORY LEVEL WINDS...BUT HAVE GONE
AHEAD AND ISSUED WIND ADVISORY FOR THE ENTIRE FORECAST AREA FROM
03Z-09Z.

QUIETER CONDITIONS FOR THURSDAY WITH COOLER CONDITIONS...BUT STILL
WELL ABOVE NORMAL FOR LATE DECEMBER. SUBSIDENCE OVERNIGHT WILL LIMIT
MIXING HEIGHTS INTO THURSDAY...AND PROVIDE FOR DIMINISHING WINDS
LATE TONIGHT INTO THURSDAY.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 415 PM EST WED DEC 23 2015

NUMEROUS CHALLENGES ARE AT HAND THIS PERIOD INCLUDING AMOUNTS AND
TIMING OF HEAVY RAIN AND CHANCES FOR WINTRY WEATHER EARLY NEXT WEEK.
TWO MORE ROUNDS OF RAINFALL ARE EXPECTED SATURDAY THROUGH MONDAY
NIGHT AS ADDITIONAL ENERGY IN THE FORM OF SHORT WAVE TROFS EJECTS
NORTHEAST INTO THE FORECAST AREA. ANTECEDENT MOISTURE INITIALLY IS
UNFAVORABLE FOR FLOODING...ALTHOUGH BY THE END OF THE WEEKEND...
SOILS SHOULD BECOME SATURATED INCREASING RUNOFF. NCEP/WEATHER
PREDICTION CENTER AND OHIO RFC BOTH FAVOR A SOUTH SHIFT IN THE AXIS
OF HEAVIEST RAINFALL. THE NORTH AMERICA ENSEMBLE FORECAST SYSTEM
INDICATED THE BEST CHANCE FOR RIVER FLOODING ARE NEXT TUESDAY INTO
WEDNESDAY. SO AT THE MOMENT...EXPECT RISES ON RIVES BY LATE MONDAY
WITH SOME RIVERS POSSIBLY FLOODING TUESDAY INTO WEDNESDAY.

AFTER COORDINATION WITH SURROUNDING OFFICES...MADE SOME CHANCES TO
THE WEATHER MONDAY INTO MONDAY NIGHT. BOTH THE GFS AND ECMWF SHOW
MUCH BELOW CONFIDENCE IN ANY SOLUTION EARLY NEXT WEEK...ALTHOUGH DID
FAVOR THE GFS SLIGHTLY IN THE HANDLING OF THE SYSTEM. BELIEVE THE
GFS IS HANDLING THE ENERGY BETTER IN A PARTIALLY CUT OFF PATTERN.
FOR NOW...HAVE A RAIN/SNOW MIX MOST AREAS MONDAY AND MONDAY NIGHT...
BUT STILL AM VERY UNCERTAIN HOW THIS THIRD ROUND OF PRECIPITATION
WILL PLAY OUT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 117 PM EST WED DEC 23 2015

PREFRONTAL TROUGH MOVING ACROSS THE AREA WILL ALLOW SHOWERS AND
ISOLATED TO SCATTERED THUNDERSTORMS TO OVERSPREAD NORTHERN INDIANA
THROUGH 23Z. A DIFFUSE SFC WARM FRONT CONTINUES TO LIFT NORTHWARD
ACROSS CENTRAL/NORTH CENTRAL INDIANA AND CONDITIONS HAVE IMPROVED
TO MVFR SOUTH OF THIS FRONT AT KFWA. IFR CONDITIONS PERSIST AT
KSBN ALTHOUGH MAY SEE SOME IMPROVEMENT TO LOWER END MVFR AT KSBN
ALSO. DID MAINTAIN TSRA MENTION FOR BOTH TERMINALS THIS
AFTERNOON...ALTHOUGH SOMEWHAT LIMITED INSTABILITY IN ASSOCIATION
WITH THE PREFRONTAL TROUGH MAY KEEP TSRA MORE
ISOLATED...PARTICULARLY AT KSBN. SHOWERS/ISO-SCT STORMS WITH
PREFRONTAL TROUGH SHOULD SHIFT EAST OF KFWA IN THE 00Z-02Z
TIMEFRAME WITH ADDITIONAL SCATTERED SHOWERS/STORMS POSSIBLE WITH
THE APPROACH OF THE COLD FRONT. CONFIDENCE IN COVERAGE WITH THE
COLD FRONT REMAINS SOMEWHAT LOWER HOWEVER. A PERIOD OF VERY GUSTY
WINDS IS EXPECTED WITH THE COLD FRONT TONIGHT...AIDED BY A VERY
STRONG RISE/FALL PRESSURE COUPLET ASSOCIATED WITH DEPARTING SFC
LOW PRESSURE. WINDS TO SUBSIDE LATE TONIGHT INTO EARLY THURSDAY
MORNING...WITH MAINLY VFR CONDITIONS EXPECTED FOR THURSDAY.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO 4 AM EST
     /3 AM CST/ THURSDAY FOR INZ003>009-012>018-020-022>027-
     032>034.

MI...WIND ADVISORY FROM 10 PM THIS EVENING TO 4 AM EST THURSDAY FOR
     MIZ077>081.

OH...WIND ADVISORY FROM 10 PM THIS EVENING TO 4 AM EST THURSDAY FOR
     OHZ001-002-004-005-015-016-024-025.

LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046.

     GALE WARNING UNTIL 7 AM EST THURSDAY FOR LMZ043-046.

&&

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...SKIPPER
AVIATION...MARSILI

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