Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 281114
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
614 AM EST FRI NOV 28 2014

.SYNOPSIS...
ISSUED AT 334 AM EST FRI NOV 28 2014

CLOUDY SKIES AND UNSEASONABLY COLD TEMPS WILL CONTINUE THROUGH
TODAY WITH AFTERNOON HIGHS RANGING FROM THE UPPER 20S NORTH TO THE
MID 30S SOUTH. MUCH WARMER AIR WILL OVERSPREAD THE REGION THIS
WEEKEND WITH HIGHS TOMORROW EXPECTED TO TOP OUT IN THE MID TO
UPPER 40S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM EST FRI NOV 28 2014

DISTURBANCE ALOFT EMBEDDED WITHIN POTENT JET STREAK ACRS ND WILL
SHEAR SEWD TDA WITHIN CONTD NW FLW ALOFT. WRN PERIPHERY OF POLAR
RIDGE IS EXTREMELY DRY AS INDICATED IN UPSTREAM KDVN/KILX 00Z RAOBS
AND NO DOUBT BORNE OUT IN TOP DOWN SATURATION FAILURE CURRENTLY SEEN
FM SW WI INTO CNTRL IL. VAST MAJORITY OF 00Z BASED GUIDANCE TAKES
STGST 295-300K PRES PERTURBATION ACRS CNTRL LWR MI DIRECTED ALG NOSE
OF STGR LL MSTR FLUX ALIGNED W/EWD WKNG JET STREAK. HWVR THIS MAY
YET CLIP FAR NERN ZONES LT THIS AFTN/EARLY EVE SHLD SUB CLD PRES
DEFICITS ERODE SUFFICIENTLY. REGARDLESS HAVE GENERALLY CUT POPS
THROUGHOUT IN WHAT WILL BE A NON MEASURABLE EVENT AT MOST.

EVEN THOUGH LL WAA RAMPS SIGLY THIS AFTN ON BACKSIDE OF POLAR RIDGE
ONE MORE ROUND OF WELL BLO NORMAL TEMPS XPCD GIVEN COLD START AND
INCIPIENT CLD CVR. HWVR THIS WILL CONVERSELY HOLD TEMPS UP TONIGHT
W/NR STEADY TEMPS XPCD AFT TEMPS PEAK THIS AFTN.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM EST FRI NOV 28 2014

ROLLER COASTER TEMPS ARE THE MAIN STORY FOR THIS LONG TERM PERIOD AS
PERTURBED BUT LARGELY ZONAL FLOW KEEPS CHANCES FOR HIGH IMPACT
WEATHER AT A MINIMUM. SOUTHERN GREAT LAKES WILL BE WELL ENTRENCHED
IN THE WARM SECTOR OF SURFACE LOW PRESSURE DEVELOPING OVER THE UPPER
MIDWEST ON SATURDAY. 850MB TEMPS SURGE INTO THE MID TEENS BY LATE
SATURDAY BUT STUBBORN LOW LEVEL INVERSION WILL PREVENT US FROM FULLY
CAPITALIZING ON THIS WARM AIR ALOFT. EXPECT PERSISTENT AND
RELATIVELY THICK STRATUS DECK...ALONG WITH LOW SUN ANGLE...WILL
PREVENT ANY SUBSTANTIVE PBL MIXING. NUDGED SATURDAY`S HIGHS DOWN A
BIT TO BE MORE IN LINE WITH LATEST RAW GUIDANCE BUT STILL MAINTAINED
TEMPS AROUND 50F IN OUR SOUTHWEST OUT OF RESPECT FOR VERY WARM
CONDITIONS RIGHT ABOVE THE SURFACE. MODELS CONTINUE TO GENERATE
LIGHT QPF IN WAA REGIME LATE SATURDAY INTO SUNDAY BUT STILL THINK
CHANCES OF SEEING ANY PRECIP IN OUR AREA DURING THIS TIME ARE VERY
LOW. MOISTURE DEPTH SEEN ON FORECAST SOUNDINGS IS AWFULLY THIN FOR
THE PRODUCTION OF HYDROMETEORS. FURTHERMORE...ENTIRE CLOUD LAYER IS
ABOVE FREEZING WITH NO POTENTIAL FOR MIXED PHASED/BERGERON PROCESSES
TO OCCUR. SYNOPTIC FORCING IS VIRTUALLY NON-EXISTENT WITH JUST SOME
BROAD/WEAK MOIST ISENTROPIC ASCENT IN THE VERY LOW LEVELS OF THE
TROPOSPHERE. IF ANYTHING...EXPECT JUST SOME PATCHY DRIZZLE...MAINLY
CONFINED TO SATURDAY NIGHT WITH A LITTLE BETTER THETA-E SURGE.

SLIGHTLY BETTER CHANCES FOR PRECIP LATE SUNDAY AS COLD FRONT SWEEPS
THROUGH THE AREA. GOOD LOW LEVEL CONVERGENCE SHOULD GENERATE A FEW
LIGHT RAIN SHOWERS...ESPECIALLY IN OUR SOUTHEAST WHERE DEEPER
MOISTURE WILL RESIDE. SURFACE FRONT WILL CLEAR OUR CWA BY SUNDAY
NIGHT AND SIGNAL THE START OF STRONG CAA...WITH 850MB TEMPS
RETURNING TO ALMOST -10C. EXPECT MOST PRECIP WILL END BY THE TIME
TEMPS TURN COLD ENOUGH FOR SNOW. SOME CONCERN FOR A SECONDARY VORT
MAX TO SWING THROUGH AND LIGHT UP AN ELEVATED FGEN BAND OVER OUR
AREA ON MONDAY...AS SEEN IN THE 00Z GEM AND TO A LESSER EXTENT THE
ECMWF. WILL KEEP AN EYE ON IT BUT THE GEM SOLUTION APPEARS TO BE
LARGELY AN OUTLIER AND WILL LEAN TOWARD DRIER CONSENSUS.

MIDDLE OF THE WEEK LOOKS RELATIVELY DRY WITH THE NEXT TROUGH NOT
ARRIVING UNTIL LATE THURSDAY OR FRIDAY. TEMPS WILL MODERATE SOMEWHAT
BY THE END OF NEXT WEEK BUT STILL HOLDING AROUND AVERAGE FOR EARLY
DECEMBER.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 609 AM EST FRI NOV 28 2014

VFR CONDS XPCD THROUGH THE PD. SHEARING DISTURBANCE ALOFT ACRS WI
INDUCING VIGOROUS MID LVL BASED RADAR ECHO FM SRN WI INTO NW IN YET
UNABLE TO OVERCOME SATURATION VOID EXISTING BLO CLD BASE. XPC THIS
WILL CONT TO BE THE CASE THROUGH THE DAY W/CONTD DRY ENTRAINMENT AS
LL SWRLY FLW INCREASES EVEN THOUGH SECONDARY WAVE SEEN TURNING OUT
ACRS WRN ND WILL LIKELY ILLICIT A EVEN STGR MID LVL FGEN RESPONSE LT
THIS AFTN BUT AGAIN XPCD TO LIE UP ACRS SE MI.

&&

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

$$

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


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