FXUS63 KTOP 111706
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1105 AM CST FRI DEC 11 2009

.AVIATION...FOR 18Z TAFS.

VFR CONDITIONS SHOULD PERSIST THROUGH 12Z SAT. SOUTHERLY FLOW WILL 
PERSIST IN THE LOWER LEVELS THROUGH THE PERIOD. THIS WILL ALLOW 
WARMER TEMPERATURES AND HIGHER DEWPOINTS TO MOVE NORTH INTO THE 
AREA. ONLY POTENTIAL ISSUE TONIGHT WOULD BE FOG AS HIGHER DEWPOINTS 
MOVE OVER THE SNOWPACK HOWEVER AT THIS TIME GIVEN THE LIMITED 
MELTING/SNOWPACK SOUTH OF THE AREA I DO NOT SEE THIS BEING LIKELY TO 
OCCUR. HOWEVER WE WILL HAVE TO MONITOR FOR THE POTENTIAL FOR MVFR 
VIS CONDS OVERNIGHT. MORE ORGANIZED WAA AND MOISTURE ADVECTION WILL 
OCCUR SAT WITH SOME MVFR STRATUS FCST TO DEVELOP AND THIS COULD 
IMPACT THE TAF SITES AROUND 18Z SAT. IT WOULD APPEAR THE LOWER CIGS 
WOULD IMPACT MHK INITIALLY AND SPREAD EAST.  

OMITT

&&

.PREV DISCUSSION... /ISSUED 341 AM CST FRI DEC 11 2009/ 

DISCUSSION...

EARLY MORNING WATER VAPOR SATELLITE LOOP SHOWS SHORTWAVE TROUGH 
MOVING INTO CALIFORNIA OFF THE EASTERN PACIFIC. THE SURFACE HIGH 
WILL CONTINUE TO MOVE TO THE EAST TODAY WITH SOUTHERLY WINDS ACROSS 
THE CWA. WARMER TEMPERATURES AND HIGHER DEW POINTS WERE POISED 
ACROSS SOUTHERN OKLAHOMA INTO NORTH TEXAS THIS MORNING. ADVECTION OF 
WARMER AIR WILL LEAD TO TEMPERATURES BEING ABOUT 5 TO 10 DEGREES 
WARMER ACROSS THE CWA TODAY. COOLEST OVER THE DEEPER SNOW PACK.

TONIGHT WARM AIR AND MOISTURE ADVECTION OCCUR AHEAD OF THE SHORTWAVE 
TROUGH ACROSS EASTERN KANSAS. LOW LEVEL MOISTURE PROJECTIONS SHOW 
INCREASING MOISTURE LATE TONIGHT IN THE 925MB TO 850 MB LAYER 
FORMING LOW STRATUS AND PERHAPS SOME PATCHY FOG AS WELL. ISENTROPIC 
LIFT IS MOST PRONOUNCED FROM SOUTHEAST KANSAS INTO MISSOURI ON 
SATURDAY AND UPWARD VERTICAL MOTIONS INCREASE TOWARD LATE MORNING IN 
THE SATURATED LOW LAYERS. LACK OF MOISTURE IN THE DENDRITIC GROWTH 
ZONE WILL LEAD TO SOME DRIZZLE OR FREEZING DRIZZLE ACROSS MUCH OF 
THE CWA SATURDAY AFTERNOON. THE SHORTWAVE TROUGH WILL MOVE INTO 
EASTERN KANSAS IN THE AFTERNOON THEN EXIT BY EARLY EVENING THUS WILL 
LIMIT DRIZZLE CHANCES TO THE AFTERNOON AND EVENING HOURS ONLY. AFTER 
MID EVENING OMEGA DECREASES RAPIDLY IN AREA OF SUBSIDENCE IN THE 
WAKE OF THE WAVE AND WILL REMOVE FREEZING DRIZZLE FROM FORECAST 
AFTER 06Z SUNDAY. ON SUNDAY WARM ADVECTION ONCE AGAIN OCCURS IN 
ADVANCE OF ANOTHER SHORTWAVE TROUGH EMERGING FROM THE ROCKIES SUNDAY 
NIGHT. THIS WAVE WILL BRING A COLD FRONT THROUGH THE EASTERN PARTS 
OF KANSAS SUNDAY NIGHT. THERE WILL BE A PERIOD OF ISENTROPIC LIFT 
OVER THE LOW LEVEL COLD AIR AND SURFACES SATURATE NORTH OF THE 
BORDER IN SOUTHERN NEBRASKA SO WILL LEAVE DRY FOR NOW BUT LATER 
SHIFTS MAY NEED TO ADD SOME LIGHT FREEZING DRIZZLE TO THE NORTHERN 
ROW OF COUNTIES WITH NEXT MODEL RUN. A STRONG COLD FRONT WILL MOVE 
THROUGH LATE SUNDAY NIGHT WITH ARCTIC COLD IN ITS WAKE. HAVE LOWERED 
TEMPERATURES FROM SUNDAY NIGHT THROUGH MID WEEK AS ARCTIC HIGH 
BUILDS INTO THE AREA.

53

&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$