Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 052340
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
740 PM EDT SAT JUL 5 2014

.SYNOPSIS...
ISSUED AT 400 PM EDT SAT JUL 5 2014

HIGH PRESSURE OVER OHIO WILL CONTINUE MOVING EAST WITH WARMER AND
MORE HUMID AIR SPREADING INTO OUR AREA BEHIND IT. AN UPPER LEVEL
TROUGH MOVING ACROSS THE AREA TONIGHT MAY CAUSE SCATTERED SHOWERS
OVER WESTERN PARTS OF THE AREA LATE. THERE IS A GOOD CHANCE OF
THUNDERSTORMS ACROSS THE ENTIRE AREA BY SUNDAY NIGHT AS A COLD
FRONT MOVES THROUGH. ANOTHER COLD FRONT IS EXPECTED TO MOVE
THROUGH THE AREA ON TUESDAY... LIKELY BRINGING ANOTHER ROUND OF
STORMS. LOWS TONIGHT WILL BE IN THE LOWER 60S WITH HIGHS SUNDAY
MAINLY IN THE LOWER 80S.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 400 PM EDT SAT JUL 5 2014

INTENSE MESOVORT IN VICINITY OF QUAD CITIES AREA AT 19 UTC PROGGED
INTO NWRN INDIANA ABOUT 04 UTC. AN INTENSE MID LEVEL MOISTURE
GRADIENT AND FOCUSED MID LEVEL LAYER ASCENT...WITHIN BROADER
30-40M/12 HR MID LEVEL HEIGHT FALLS...MAY BE SUFFICIENT FOR LIGHT
SHRA LATE TONIGHT/TOWARD DAYBREAK IN NWRN THIRD CWA. KDVN VWP WELL
BACKED AND STRONG/35 KTS AT 10 KFT AGL...A TESTAMENT TO MESOVORT
STRENGTH. HOWEVER...BY FAR THE LIMITING CONVECTIVE MAINTENANCE
FACTOR IS THE PRESENCE OF EXTREME DOWNSTREAM STABILITY. NAM APPEARS
A BIT TOO AGGRESSIVE WITH MESOVORT AND SUBSEQUENT
FEEDBACK...PREFERENCE LIES TOWARD MORE SEDATE SREF/RUC13/LCL WRF
SCENARIO GIVEN POOR DOWNSTREAM LOW/MID LEVEL THERMAL PROFILES. BY
MIDDAY/AFTERNOON MODERATE DESTABILIZATION ANTICIPATED AT LEAST
ACROSS NWRN HALF OF CWA WITH MLCAPE RANGING FROM 1500-2500 J/KG
DEPENDENT ON DEGREE OF INSOLATION/LYSIS OF MORNING ALTOCU DECK.
MAJORITY OF INTENSE CONVECTION ON SUNDAY EXPECTED ALONG COLD FRONT
DROPPING SEWD THROUGH WESTERN LAKES/NORTHERN MS VLY WITH SIGNIFICANT
INSTABILITY/MODERATE DEEP LAYER SHEAR OVERLAP. STILL LESSER
PROBABILISTIC CHANCE FOR A FEW STORMS TO DEVELOP WITHIN WEAK
PREFRONTAL TROF COINCIDENT WITH MAXIMUM LATE AFTERNOON/EARLY EVENING
INSOLATION FROM SWRN MI THROUGH NWRN IN/NERN IL WITH NEARLY HALF OF
UPSTREAM DEEP LAYER SHEAR...WITH VALUES ON ORDER OF 20-25 KTS WITHIN
0-6KM ACROSS NWRN CWA. SUBSTANTIAL HIGH LEVEL CANOPY AT PRESENT
FOLLOWED BY MID LEVEL DECK AND INCREASED GRADIENT FLOW ALONG WITH
DEPARTING LOW LEVEL THERMAL TROF SUGGESTS NOT AS STRONG RADIATIONAL
LOSSES OVERNIGHT WITH SLIGHT UPWARD BUMP IN TEMPS...NEARER CONSENSUS
BLEND. ADDITIONALLY VARIABLE MORNING CLOUD COVER AND LOW LEVEL
THERMAL RIDGE AXIS HOLDING UPSTREAM TOMORROW AFTERNOON HAVE
SLIGHTEST OF DOWNWARD NUDGE ON SUN.

&&

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 400 PM EDT SAT JUL 5 2014

LARGE SCALE PATTERN WILL AMPLIFY A BIT EARLY NEXT WEEK AS PACIFIC
JET ENERGY SNAKES ITS WAY THROUGH THE NORTHERN CONUS AND CARVES OUT
A DECENT TROUGH OVER THE GREAT LAKES. PAIR OF EMBEDDED SHORTWAVES
WILL BRING TWO PERIODS OF FOCUSED HEIGHT FALLS AND ASSOCIATED COLD
FRONTAL PASSAGES. THE FIRST WILL ARRIVE SUNDAY NIGHT INTO MONDAY.
BEST CVA AND LEFT EXIT JET SUPPORT PASS NORTH OF OUR CWA BUT STRONG
WSW LLJ WILL ADVECT UPSTREAM THETA-E PLUME INTO OUR AREA OVERNIGHT.
THIS WILL GENERATE ADEQUATE MOISTURE/ELEVATED INSTABILITY TO SUPPORT
SCT SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF LOW LEVEL
CONVERGENT BOUNDARY BUT UNFAVORABLE TIMING AND RATHER ILL-DEFINED
FORCING ALOFT SUGGEST HOLDING WITH JUST HIGH CHANCE POPS FOR NOW.
DESPITE IMPRESSIVE WIND/SHEAR PROFILES ALOFT...SEVERE WEATHER
POTENTIAL IS ALSO LOW FOR GENERALLY THE SAME REASONS. BETTER
INSTABILITY REMAINS CONFINED TO OUR WEST SUNDAY EVENING AND FRONT
LOOKS TO CLEAR MOST OF THE CWA BEFORE DIURNAL DESTABILIZATION ON
MONDAY. HIGHER POPS/SEVERE RISK MAY BE NECESSARY IF A WELL ORGANIZED
MCS/MCV CAN DEVELOP UPSTREAM AND PROPAGATE INTO OUR AREA BUT
LIKELIHOOD CURRENTLY APPEARS LOW BASED ON OVERALL MEAGER NOCTURNAL
INSTABILITY AND SYNOPTIC FORCING. A SLOWER FRONTAL PASSAGE COULD
ALSO SUPPORT HIGHER POPS/SEVERE RISK EARLY MONDAY AFTERNOON IN OUR
SOUTHEAST BUT BETTER CHANCES APPEAR JUST OUTSIDE OUR CWA.

SIMILAR STORY FOR TUESDAY AS SECONDARY SHORTWAVE/COLD FRONT CROSSES
THE REGION. CVA AND UPPER JET SUPPORT ARE MUCH MORE FAVORABLE FOR
OUR CWA DURING THIS WAVE BUT INSTABILITY IS QUESTIONABLE. BEST LOW
LEVEL MOISTURE IS SHUNTED SOUTHWARD AND MAY BE DIFFICULT TO ACHIEVE
ANY DECENT DIURNAL HEATING WITH EXPECTED EARLY ARRIVAL OF CLOUDS AND
PRECIP. LATEST 12Z GFS ONLY SHOWS AROUND 500 J/KG OF 0-1KM MLCAPE.
STRENGTHENING MID/UPPER LEVEL JET YIELDS SOME IMPRESSIVE DEEP LAYER
SHEAR VALUES THOUGH AND ORGANIZED SEVERE WEATHER COULD BE POSSIBLE
IF ENOUGH DESTABILIZATION OCCURS. REGARDLESS OF SEVERE WEATHER
CHANCES...TUESDAY IS SHAPING UP TO BE OUR BEST CHANCE FOR WIDESPREAD
RAIN AND HAVE NUDGED POPS INTO LIKELY CATEGORY. DRY CONDITIONS
EXPECTED FOR THE REST OF THE WEEK AS THETA-E TROUGH AND ANTICYCLONIC
BUBBLE RETURN TO THE GREAT LAKES. AFTER A WARM START TO THE
WEEK...TEMPERATURE AND HUMIDITY LEVELS WILL ALSO EASE AS LOW LEVEL
FLOW VEERS TO A MORE NORTHWESTERLY DIRECTION.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 735 PM EDT SAT JUL 5 2014

HIGH PRESSURE OVER SWRN PA MOVG AWAY FROM OUR AREA THIS EVE AS A
CDFNT OVER THE NRN HIGH PLAINS APPROACHES. THIS WILL RESULT IN
INCRSG SWLY FLOW WHICH WILL BRING WARM/MOIST/UNSTABLE AIR BACK
INTO THE AREA BY SUNDAY. AN MCV OVER CENTRAL IL WAS MOVG EAST AND
PRODUCING A FEW SHRA TO OUR WEST THIS EVE. THIS FEATURE EXPECTED
TO MOVE ACROSS NRN/CENTRAL INDIANA TONIGHT BUT DEEPER MOISTURE
STILL LACKING AS IT MOVES THROUGH SO EXPECT NO SGFNT IMPACT AT THE
TERMINALS AND LEFT OVERNIGHT TAFS DRY WITH JUST VFR STRATO/ALTO CU
CIGS. APCHG CDFNT AND ANOTHER SHRTWV DROPPING SE TOWARD THE AREA
ON SUNDAY MAY COMBINE WITH THE INCREASINGLY UNSTABLE AIRMASS TO
CAUSE SCT TSRA IN THE AFTN BUT ATTM CHANCES TOO LOW TO MENTION IN
TAFS... WITH BETTER CHANCES SUNDAY NIGHT AS STRONGER FORCING MOVES
INTO THE AREA.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT FROM SUNDAY AFTERNOON THROUGH LATE
     SUNDAY NIGHT FOR INZ003.

MI...BEACH HAZARDS STATEMENT FROM SUNDAY AFTERNOON THROUGH LATE
     SUNDAY NIGHT FOR MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 PM SUNDAY TO 4 AM EDT MONDAY FOR
     LMZ043-046.

&&

$$

SYNOPSIS...JT
SHORT TERM...MURPHY
LONG TERM...AGD
AVIATION...JT


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