Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 290830
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
330 AM EST SAT NOV 29 2014

.SYNOPSIS...
ISSUED AT 330 AM EST SAT NOV 29 2014

A DREARY WEEKEND IS EXPECTED UNDER CLOUDY SKIES WITH PATCHY
DRIZZLE EXPECTED TO DEVELOP THIS AFTERNOON AND CONTINUE TONIGHT
TEMPERATURES WILL BE MUCH WARMER WITH HIGHS IN THE 40S.
EVEN WARMER AIR WILL OVERSPREAD THE AREA ON SUNDAY BUT ALSO BRING
ABOUT A CHANCE FOR SHOWERS. HIGHS ARE EXPECTED TO REACH INTO THE
50S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM EST SAT NOV 29 2014

ROLLER COASTER TEMPS THIS PD AS DOWNSTREAM LL THERMAL RIDGE CONTS
TO BLOSSOM IN RESPONSE TO DEEPENING CYCLONE TAKING SHAPE ACRS THE
NRN PLAINS. ONLY FLY IN THE OINTMENT IS POTENTIAL DZ/--RA THIS
AFTN IN TANDEM W/INITIAL NWD LL MSTR SURGE COMMENSURATE W/LIKELY
STRATUS DVLPMNT. HWVR MSTR REMAINS SHALLOW AND WELL BLO BTR
FORCING ALOFT THUS FVRG DZ VS --RA. REGARDLESS PRIOR APCH OF LOW
CHC POPS FOR POTENTIAL LOW END MEASURABLE EVENT FVRD AND RETAINED.
OTRWS NON-DIURNAL TEMPS W/STEADY WARMING XPCD THROUGH THE PD.

&&

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 330 AM EST SAT NOV 29 2014

SUNDAY WILL BEGIN VERY MILD WITH SOUTHWEST FLOW AND WARM/MOIST AIR
ADVECTION PUSHING TEMPS INTO THE 50S...AND PERHAPS LOWER 60S IN OUR
SOUTHEAST...AHEAD OF AN APPROACHING COLD FRONT. SHALLOW AND WEAK
290K MOIST ISENTROPIC ASCENT WILL CONTINUE TO SUPPORT SOME PATCHY
DRIZZLE THROUGH THE MORNING HOURS AHEAD OF THE MAIN SURFACE FRONT.
SATURATED LAYER REMAINS CONFINED TO THE LOWEST 3 KFT SO QPF WILL BE
VERY LIGHT AND SCATTERED. SYNOPTIC FORCING ALONG THIS FRONT WONT DO
MUCH TO HELP PRECIP CHANCES EITHER. BEST DCVA/HEIGHT FALLS PASS WELL
TO OUR NORTH AND UPPER JET PLACEMENT IS NOT FAVORABLE FOR OUR AREA.
WEAK 1000-850MB CONVERGENCE WILL AID SHOWER CHANCES BUT MAINLY IN
OUR SOUTHEAST ZONES WHERE SLIGHTLY DEEPER MOISTURE WILL RESIDE. LOW
CHANCE POPS SEEM PRUDENT FOR MOST OF OUR CWA WITH JUST A FEW
HUNDREDTHS OF QPF EXPECTED.

MAIN STORY WILL BE RETURN TO MUCH COLDER TEMPS BEHIND THIS FRONT.
850MB TEMPS RETURN TO ALMOST -10C BY MONDAY MORNING. A BRIEF MIX IS
POSSIBLE BEHIND EXITING SURFACE FRONT SUNDAY NIGHT BUT STILL LOOKS
LIKE DRY AIR ADVECTION WILL BE QUICK ENOUGH AND STRONG ENOUGH TO CUT
OFF PRECIP BEFORE TEMPS DROP BELOW FREEZING. A FEW LAKE EFFECT SNOW
SHOWERS ARE ALSO POSSIBLE IN OUR NORTHWEST ZONES ON MONDAY MORNING
GIVEN MODEST LAKE INDUCED INSTABILITY. VERY STRONG SUBSIDENCE
INVERSION WILL CAP CONVECTIVE DEPTHS TO AROUND 3 KFT BUT SEVERAL
HI-RES MODELS ARE SHOWING GOOD SUPERSATURATION WRT ICE IN FORECAST
SOUNDINGS FOR AT LEAST A SHORT TIME MONDAY MORNING. THIS WILL
PROBABLY BE ENOUGH TO GENERATE A FEW FLURRIES BUT AMOUNTS AND
IMPACTS...IF ANY...WILL BE VERY LIMITED. HIGHS ON MONDAY WILL BE
20-25 DEGREES COLDER THAN SUNDAY AND IT WILL FEEL EVEN COLDER WITH A
STEADY NORTHWEST WIND OF 15-20 MPH.

GENERALLY DRY AND COLD CONDITIONS EXPECTED LATE MONDAY THROUGH
WEDNESDAY. A WEAK FRONT TRIES TO PUSH THROUGH THE REGION ON
WEDNESDAY BUT AGAIN...BEST FORCING IS WELL TO OUR NORTH AND MOISTURE
RETURN IS SEVERELY HAMPERED BY STUBBORN ANTICYCLONE. WILL THEREFORE
MAINTAIN DRY FORECAST THROUGH WEDNESDAY NIGHT. MODELS STILL DISAGREE
ON TIMING AND EVOLUTION OF NEXT LOW AMPLITUDE WAVE SET TO FLOW
THROUGH THE REGION SOMETIME DURING THE END OF THE WEEK...A SHEARED
OUT REMNANT OF A DECENT WAVE CURRENTLY OVER THE NORTH PACIFIC. 00Z
GFS MAINTAINS A MUCH FASTER...AND COLDER...SYSTEM COMPARED TO THE
ECMWF AND GEM. WILL HOLD WITH LOW CHANCE POPS FOR BOTH THURSDAY AND
FRIDAY WITH PLENTY OF TIME FOR ADJUSTMENTS AS THIS PACIFIC WAVE IS
INGESTED INTO FAST/ZONAL FLOW ACROSS NORTH AMERICA. TEMPS SLOWLY
MODERATE BY THE SECOND HALF OF THE WEEK...BUT ONLY TO VALUES NEAR
NORMAL FOR EARLY DECEMBER.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 118 AM EST SAT NOV 29 2014

SFC CYCLONE DVLPG OVR THE WRN DAKOTAS WILL DEEPEN CONSIDERABLY THIS
PD AS IT LIFTS OUT TWD JAMES BAY. CORRESPONDING WARM SECTOR WILL
DEEPEN RAPIDLY TDA AS SIG LL THERMAL RIDGE ADVTS EWD INTO THE OH
VALLEY. FLEDGLING MSTR RTN OUT OF THE WRN GOMEX LIKELY ENOUGH WITHIN
WEAKLY FORCED BNDRY LYR TO PROMOTE SOME DZ THIS AFTN W/MVFR FUEL ALT
CONDS LIKELY.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LMZ043-046.

&&

$$

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


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