FXUS63 KIWX 181152
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
651 AM EST THU NOV 18 2004

.AVIATION...
EXACERBATING SITU THIS AM WRT TO TAFS. MODEL GUIDANCE AS A WHOLE 
MUCH TOO PESSIMISTIC GIVEN UPSTREAM TRENDS ACRS IL INTO WRN IN. 
INCOMING MID/HIGH CLD SHIELD RAPIDLY OVERSPREADING THE AREA HELPING 
MATTERS AS IS RENEWED BUT SCT SHRA. OF IMMEDIATE CONCERN IS AREA OF 
LIFR WHICH HAD DEVELOPED UPSTREAM IN WI ALG WK SFC TROUGH. MORE OF 
AN ISSUE FOR SBN AS BNDRY PIVOTS SWD IN RESPONSE TO BACKING LL FLW 
AHD OF STG SRN STREAM LOW HEADED FOR THE AREA TONIGHT. FWA SHLD STAY 
S BUT POSES MORE OF A CHALLENGE GIVEN LG STRATUS WEDGE OVR OH LIKELY 
NOT BREAKING UP THIS AFTN AND POTENTIAL TO ADVT WWD INTO FWA AREA 
LTR TDA. DAY SHIFT WILL NEED TO MONITOR THAT OTHERWISE FOLLOWING 
MORE OPTIMISTIC RH TRENDS SEEN IN SHRT TERM RUCII DATA AND 
OBSERVATIONS.

&&

.SHORT TERM...
IMPRESSIVE SRN STREAM SYS POISED TO OPEN AND EJECT NE AHD OF 
POWERHOUSE NRN STREAM WV COMING INTO BC THIS AM. FLOOD GATE OF MSTR 
IN PLACE DOWNSTREAM W/00Z H2O PLOT TELLING THE TALE AS MANY RAOBS 
AOA 200% OF NORMAL. MSTR PLUME NOT GOING ANYWHERE TOO SOON AND GIVEN 
CONTD PROXIMITY OF LL THETA GRADIENT AND WK UPR WV ALG SRN EDGE OF 
WESTERLIES UPSTREAM OVR WI...HAVE ADDED MORE POPS THIS AFTN S OF 
IN/MI BORDER. ALREADY COMPOSITE RADARS SHOWING QUITE A FEW SHOWERS 
OVR CNTRL/SRN WI AND INTO NRN IL AND MAY HAVE TO BACK THINGS UP 
FURTHER IN GRIDS BEFORE ALL IS SAID AND DONE ON THIS FTR FOR TDA. 
OTHERWISE OTHER PROBLEM THAT BEARS WATCHING IS FOG WHICH HAS BECOME 
DENSE ACRS NE IN CONJUCTION W/LOSS OF MID LVL CLD DECK...ALTHOUGH 
THAT APPEARS TO BE SHRT LIVED GIVEN ADDNL MID CLDS STREAMING EWD AHD 
OF WK WV IN WI AND MIGHT SQUEEK BYE WITHOUT HAVING TO POST AN 
ADVISORY. LTL CHC FOR INSOLATIVE INPUT THIS AFTN AND VRY LIMITED 
MIXING AGAIN SUGGEST CUTTING TEMPS BACK SOME FOR THIS AFTN ALTHOUGH 
PASSAGE OF WI UPR TROUGH AND BACKING LL WINDS IN RESPONSE 
TO EJECTING SRN WV LOOK TO PULL DOWN A BIT DRIER AIR LOCATED UP N 
BUT SRN EXTENT BEFORE STALLING TONIGHT HIGHLY QUESTIONABLE. HAVE MY 
DOUBTS IT WILL MAKE IT MUCH BEYOND THE BORDER AND HAVE REFINED 
OVERNIGHT MINS TO CORRELATE. PRESENCE OF LL THETA GRADIENT AND 
INCREASING UPR SPRT IN TANDEM W/DEEP MSTR PLUME IN PLACE SPELL CAT 
TO LIKELY POPS THEN TOO EXCEPT FAR NE BY DAYBREAK FRI. 

&&

.LONG TERM...
FRIDAY THROUGH WEDNESDAY.

MODELS STILL FOCUSING MUCH OF THE PRECIP ACROSS THE FORECAST AREA 
MAINLY FRI AM...WITH THE BULK OF THE LIFT SHIFTING NORTHEAST DURING 
THE AFTERNOON. HAVE OPTED TO GO CAT POPS ALL DAY...BUT LOW END OF 
CAT POPS IN SW COUNTIES IN AFTERNOON TO SHOW SOMEWHAT OF A 
DECREASING TREND. WITH EXPECTED CLOUD CVR AND PRECIP...NOT EXPECTING 
MUCH OF A RISE IN TEMPS...WITH READINGS IN THE MID 50S LOOKING 
GOOD...ON TRACK WITH GUIDANCE. FRIDAY NIGHT REMAINS A CHALLENGE AS 
BEST LIFT WILL BE NORTH OF THE AREA BUT WITH SFC LOW STILL TO OUR 
IMMEDIATE WEST AND DEEP MSTR STILL IN PLACE...DON'T THINK IT WILL 
TAKE MUCH TO GET SOME SHOWERS OR AREAS OF RAIN...SO HAVE KEPT LIKELY 
POPS. 

THROUGH SATURDAY EVENING...CHC POPS STILL WARRANTED AS LOW BEGINS TO 
MOVE NORTHEAST ACROSS MICHIGAN AND UPPER LEVEL TROUGH MOVES CLOSER 
TO THE AREA. 850 MB TEMPS WILL RISE A FEW DEGREES...WHICH WITH SOME 
BREAKS IN THE CLOUDS EXPECTED...TEMPS SHOULD MAKE IT INTO THE 
MID-UPR 50S AND POSSIBLY INTO THE 60S. STAYING ON COOLER END OF 
GUIDANCE FOR NOW DUE TO UNCERTANTITY. PRECIP SHOULD BE CLEAR OF THE 
AREA BY LATER SATURDAY NIGHT.

DRY CONDITIONS WILL PREVAIL WITH MORE SEASONABLE TEMPERATURES 
EXPECTED ACROSS MUCH OF THE AREA THROUGH WEDNESDAY AS RIDGE TAKES 
HOLD OVER THE AREA. LATER FORECASTS WILL NEED TO ADDRESS LAKE EFFECT 
POTENTIAL LATE IN THE WEEKEND AS FAVORABLE DELTA T'S WILL 
OCCUR...BUT FETCH NOT THE BEST FOR LAKE EFFECT PRECIP OVER THE 
FAVORED COUNTIES. SOME CONCERNS NOW STARTING TO EVOLVE ON POTENTIAL 
FOR FIRST SNOWFALL OF THE SEASON IF ECMWF/GEM (AND GFS TO LESSER 
DEGREE) COME TRUE WITH STRENGTHENING LOW MOVING OUT OF THE GULF 
STATES...TRACKING OVER CENTRAL OHIO ON WEDS WITH 1000-850 MB 
THICKNESSES AOB 1530. TOO EARLY TO DEAL WITH IN GRIDS SO STATUS QUO 
FOR NOW.

&&

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

&&
AVIATION/SHORT TERM...HOLSTEN
LONG TERM...FISHER
$$