FXUS63 KIND 251630
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1130 AM EST WED NOV 25 2009

.AVIATION...DISCUSSION FOR THE 25/18Z TAFS.
BORDERLINE MVFR/IFR CEILINGS HAVE BEEN THE RULE THIS MORNING BUT 
HAVE GENERALLY BEEN IMPROVING. MODELS CONTINUED SHOWING LOTS OF LOW 
LEVEL MOISTURE...SO WL JUST GO WITH MVFR THROUGH THE TAF PERIOD.
MEANWHILE...THERE WERE STILL A FEW POCKETS OF DRIZZLE AROUND AND 
RAPID REFRESH MODEL WAS INDICATING INCREASE IN ACTIVITY AFTER 00Z 
TNGT AHEAD OF AN APPROACHING UPPER LEVEL LOW PRESSURE CENTER THAT IS 
EXPECTED TO PASS ACROSS NORTH CENTRAL INDIANA MIDDAY THANKSGIVING. 
SO...WL ADD VCSH THIS AFTERNOON PER THE CURRENT ACTIVITY AND KEEP IT 
IN TONIGHT AND TOMORROW. MODEL SOUNDINGS AND BUFKIT SUGGEST 
POTENTIAL FOR MIXED RAIN AND SNOW BY LATE MORNING...BUT WITH THAT 
BEING THAT FAR OUT AND COVERAGE IN QUESTION...WILL JUST KEEP VCSH IN 
FOR NOW. SOUTHWEST WINDS WERE GUSTING ABOVE 20 KNOTS AT TIME THIS 
MORNING AND SHOULD CONTINUE THROUGH MUCH OF THE AFTERNOON BEFORE 
DROPPING OFF SOME TONIGHT. 

&&

.PREV DISCUSSION...COOLER AND UNSETTLED WEATHER EXPECTED ACROSS THE 
AREA IN THE SHORT TERM AS A COUPLE OF POTENT UPPER AIR DISTURBANCES 
MOVE THROUGH...EVENTUALLY CARVING OUT A LONG WAVE TROUGH OVER THE 
GREAT LAKES AND OHIO VALLEY BY THURSDAY. HOWEVER...PATTERN REMAINS 
PROGRESSIVE WITH THIS TROUGH MOVING TO THE EAST COAST BY FRIDAY. 
MODELS IN GOOD AGREEMENT WITH THE MAIN FEATURES. FORECAST FOCUS 
CENTERS ON POPS ASSOCIATED WITH THE DISTURBANCES AND PRECIPITATION 
TYPE TONIGHT AND THURSDAY.

FOR TODAY...FIRST SYSTEM CURRENTLY OVER NORTHERN ILLINOIS EXPECTED 
TO MOVE ACROSS THE NORTHERN SECTIONS OF THE STATE LATER THIS 
MORNING. REGIONAL RADARS SHOWING SOME LIGHT SHOWERS ASSOCIATED WITH 
THIS SYSTEM...WHICH LOOKS TO AFFECT MAINLY THE NORTHERN SECTIONS OF 
THE FORECAST AREA LATER THIS MORNING. PRECIPITATION THREAT WITH THIS 
SYSTEM SHOULD EXIT THE AREA BY THIS AFTERNOON...BUT LIFT FROM THE 
NEXT DISTURBANCE DROPPING SOUTHEAST THROUGH THE NORTHERN PLAINS 
SHOULD BE APPROACHING THE NORTHWEST COUNTIES TOWARDS SUNSET. ALL IN 
ALL...WL CONTINUE WITH CHANCE POPS TODAY...WITH THE HIGHEST POPS IN 
THE NORTHWEST.

IN THE LATER PERIODS...INITIAL BAND OF LIFT ASSOCIATED WITH SECOND 
SYSTEM EXPECTED TO MOVE ACROSS THE AREA DURING THE EVENING HOURS 
TONIGHT. SYSTEM LOOKS PRETTY DYNAMIC...SO WILL GO WITH LIKELY POPS 
IN THE NORTH CLOSEST TO THE BEST LIFT...AND CHANCE POPS FARTHER 
SOUTH. THICKNESSES SUGGEST AIR MASS MAY BECOME COLD ENOUGH TO 
SUPPORT SOME SNOW AFT ABOUT 260800Z...SO ANY LINGERING PRECIPITATION 
LATER IN THE NIGHT MAY HAVE SOME SNOW MIXED IN.

MAIN PART OF SECOND SYSTEM EXPECTED TO MOVE THROUGH ON THURSDAY. 
WILL GO WITH LIKELY POPS OVER ABOUT THE NORTHERN TWO THIRDS OF THE 
AREA...CLOSEST TO TRACK OF THE VORTICITY MAXIMUM...AND CHANCE POPS 
FARTHER SOUTH. THICKNESSES SUPPORT A RAIN/SNOW MIX. AT THIS 
POINT...DUE TO THE LIGHT AMOUNTS AND SURFACE TEMPERATURES ABOVE 
FREEZING...NOT EXPECTING ANY ACCUMULATIONS. WILL KEEP CHANCE POPS 
FOR RAIN OR SNOW DURING THURSDAY EVENING IN THE FAR EAST AND PERHAPS 
SOME FLURRIES ELSEWHERE...BUT IT APPEARS THREAT FOR MEASURABLE 
PRECIPITATION IS DIMINISHING BY THAT TIME.

LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR TODAY AND 
THURSDAY MAY BE A COUPLE OF DEGREES ON THE WARM SIDE...SO WILL NUDGE 
THEM DOWN A BIT IN THOSE PERIODS. REMAINDER OF GUIDANCE LOOKS OK.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE. 

&&

$$

PUBLIC...JAS
AVIATION...MK