000 FXUS63 KIWX 051737 AFDIWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 137 PM EDT SUN JUL 5 2009 .AVIATION... WEAK WAVE PASSING THROUGH THIS AFTERNOON SLOWLY PRODUCING A WIND SHIFT ACROSS THE AREA HWVR FLOW IS SO WEAK THAT TERMINALS MAY NOT ESTABLISH A PREVAILING BREEZE THROUGH SUNDOWN. REMOTE CHC OF A SHWR FORMING DURING AFT HEATING IN THE NORTH ALONG WEAK BNDRY CURRENTLY SAGGING THROUGH CENTRAL MICHIGAN..BUT NOT SUFFICIENT TO MENTION IN TAFS. OTHERWISE...SCT CU DECK TO WASH OUT LATE THIS AFT WITH VFR CONDS THROUGH THE PD. && .PREV DISCUSSION... /ISSUED 615 AM EDT SUN JUL 5 2009/ SHORT TERM... TODAY THROUGH MONDAY NIGHT... RAIN HAS EXITED THE AREA BUT CLOUDS REMAIN IN THE SOUTH AND DENSE FOG HAS FORMED IN THE NORTH WHERE PARTIAL CLEARING AND CALM WINDS OCCURRED. LOW PRESSURE WAS SLOWLY MOVING SOUTHEAST THROUGH SOUTHERN ILLINOIS THIS MORNING AND WILL CONTINUE TO PULL AWAY FROM THE AREA. NORTHERN PERIPHERY OF CLOUD SHIELD WILL SLOWLY FOLLOW AND SAG SOUTH TODAY. DENSE FOG IN THE NORTH WILL BEGIN TO BURN OFF AFTER SUNRISE. DENSE FOG ADVISORY WAS ISSUED FOR THESE AREAS OF FAR NORTHERN INDIANA...LOWER MICHIGAN AND NORTHWEST OHIO WHERE VIS HAS BEEN REPORTED DOWN TO NEAR ZERO AT TIMES. ADVISORY WILL CONTINUE THROUGH 12Z UNLESS CONDITIONS IMPROVE. A WEAK SHORT WAVE AND ASSOCIATED WIND SHIFT WILL PUSH THROUGH FORECAST AREA THIS AFTERNOON AS YET ANOTHER UPPER LOW DEVELOPS ACROSS ONTARIO PROVINCES. SEVERAL WEAK SHORT WAVES LOOK TO MOVE THROUGH THE LAKES REGION AS THEY ROTATE AROUND THIS LOW. NAM TRYING TO DEVELOP A FEW ISOLATED SHOWERS WITH EACH WAVE BUT THIS LOOKS OVERDONE AS BEST DYNAMICS WILL PASS TO THE NORTH OF OUR AREA. WILL HAVE PARTLY CLOUDY SKIES TODAY FOR COMBINATION OF DEPARTING CLOUDS IN SOUTH AND ANY CU DEVELOPMENT TODAY WITH FIRST WEAK SHORT WAVE. TEMPS SHOULD WARM BACK TO NEAR 80 MOST AREAS. ANOTHER WEAK WAVE LOOKS TO PASS THROUGH ON MONDAY. SIMILAR TO TODAY WILL HAVE PARTLY TO MOSTLY SUNNY SKIES WITH LIMITED MOISTURE. HIGHS WILL BE FEW DEGREES WARMER MONDAY WITH LOWER 80S MOST AREAS. LONG TERM... TUESDAY THROUGH SATURDAY. MAIN FOCUS WILL BE AT START OF THE PERIOD WITH MODEL DISAGREEMENT ON POSSIBLE PRECIP WITH STG WAA SURGE BETWEEN TUES AFTN AND WEDS NGT. GFS OVER THE PAST SEVERAL RUNS HAS SHOWED A MCS DEVELOPING AND MOVING SE ALONG THE EDGE OF THE ANTICIPATED WAA SET TO MOVE IN BY THURS. MUCH OF THIS HAS BEEN THE RESULT OF CONVECTIVE FEEDBACK AND FOR THE MOST PART HAS BEEN DISCOUNTED. THE 00Z NAM12 HAS COME IN WITH INCREASING ISENTROPIC LIFT LATE TUES AFTN INTO WEDS MORNING...WHICH SEEMS A BIT OUT OF WHACK CONSIDERING BEST DYNAMICS AND LL FLOW WILL REMAIN FURTHER NW. 00Z GFS MAY BE HANDLING THINGS A BIT BETTER WITH INITIAL ACTIVITY DEVELOP IN THE PLAINS AND POSSIBLY TRACKING ACROSS MICHIGAN WITH ADDITIONAL DEVELOPMENT ACROSS THE AREA WEDS AFTERNOON. BOTH SCENARIOS HAVE SOME PLAUSIBILITY WITH SIMILAR PATTERNS RECENTLY GIVING THE AREA AT LEAST REMNANTS OF MCS ACTIVITY. THAT BEING SAID...THE 21Z SREF...00Z GEM GLOBAL AND ECMWF ALL POINT TOWARDS THE NE DRIER FLOW WINNING THE BATTLE AND HOLDING ANY PRECIP WELL TO THE WEST AND NORTH. MEN NUMBERS CAME IN WITH A LARGE SPREAD IN POPS FOR WEDS AND STANDARD DEVIATIONS OF 10 TO 11. COLLABORATION WITH SURROUNDING OFFICES RESULTED IN A CONSENSUS THAT AT THIS POINT WILL KEEP THINGS DRY. HOWEVER THIS IS SOMETHING THAT WILL NEED TO BE MONITORED IN THE NEXT DAY OR 2 TO SEE IF MODELS COME INTO ANY AGREEMENT. UNTIL THIS WAA MOVES IN...TEMPS WILL REMAIN IN THE 70S TO NEAR 80 INTO WEDS WITH SURGE OF WARMER AIR ARRIVING FOR THE END OF THE WEEK AS 850 MB TEMPS CLIMB TO AOA 20 C. RESULTANT INCREASING TEMPS AND SLOW INCREASE IN DEWPTS WILL GIVE INCREASING INSTABILITY THURS AND FRI AFTERNOON. NO REAL FOCUS FOR ANYTHING TO POP ON THURS...BUT A COLD FRONT MAY BE ENTERING THE AREA AS EARLY AS FRI NGT TO GIVE A CHANCE FOR SHOWERS AND STORMS. NEW ECMWF SUGGESTS ARRIVAL OF THIS FRONT COULD BE MORE INTO SAT BUT FOR NOW WILL LEAVE THINGS AS IS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...LASHLEY LONG TERM...FISHER AVIATION...LUD