FXUS63 KTOP 272126
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
326 PM CST FRI NOV 27 2009

.DISCUSSION...

MAIN FORECAST PROBLEM THROUGH SATURDAY IS TEMPERATURES.  WATER VAPOR 
LOOP SHOWS CIRRUS SPILLING OVER CENTRAL U.S. UPPER RIDGE ACROSS 
NEBRASKA.  THIS COULD BRUSH NORTHEAST KS OVERNIGHT.  PRESSURE 
GRADIENT TONIGHT SHOULD STAY STRONG ENOUGH OVER MOST OF CWA TO KEEP 
SOME MIXING...AND THUS LOW TEMPERATURES IN THE 30S.  NAM AND GFS 
BRING FRONTAL BOUNDARY INTO NC KS SATURDAY MORNING...AND DRIFT IS 
SEWD DURING THE DAY.  NAM...ESPECIALLY 18Z NAM FASTER THAN GFS IN 
TERMS OF MOVEMENT OF FRONT.  HAVE GONE WITH SLOWER GFS WHICH WAS 
SIMILAR TO PREVIOUS NAM AND GFS RUNS ON SPEED...THUS EXPECT HIGHS ON 
SATURDAY TO BE WARM AGAIN RANGING FROM NEAR 60 IN FAR NWRN CWA TO 
MID 60S IN EC KS.  COULD EVEN BE WARMER IF MORE EXTENSIVE HIGH LEVEL 
CLOUD COVER FROM SOUTHERN STREAM SYSTEM DOESN'T GET HERE BEFORE 
SUNSET.

FRONT SLIDES THROUGH THE AREA OVERNIGHT SATURDAY NIGHT INTO SUNDAY
MORNING. MOISTURE AND INSTABILITY ARE LIMITED AT THIS TIME...AND
WILL ONLY CARRY A SLIGHT CHANCE FOR SHOWERS ACROSS SE COUNTIES ON
SUNDAY AS LIFT ENSUES OVER THE BOUNDARY WITH THE UPPER TROF. HAVE
INCREASED CLOUDS AND ONLY EXPECT HIGHS IN THE 40S. WEST
NORTHWESTERLY FLOW MOVES IN BEHIND THE UPPER SHORTWAVE TROF ON
MONDAY INTO TUESDAY WITH TEMPS RECOVERING INTO THE 50S. 

DIFFERENCES IN SOLUTIONS INCREASE WED THRU FRIDAY. EC IS MORE
AGGRESSIVE AT DRAWING THE COLD AIR SOUTHWARD BY DEVELOPING A STRONG
LONGWAVE TROF ACROSS THE CENTRAL US BY LATE WEEK. GFS IS MORE
PROGRESSIVE WITH THE ENERGY AND LIFTS THE SOUTHERN LOW INTO THE
OHIO VALLEY...USHERED EASTWARD BY THE NORTHERN STREAM LONGWAVE
TROF. ANOTHER REINFORCING SHOT OF ENERGY DROPS INTO THE TROF ON
THURSDAY BEFORE EASTWARD PROGRESS LEAVES US UNDER THE UPPER RIDGE
ON FRIDAY. ENSEMBLE MEMBERS ARE SPLIT...WITH A FEW FAVORING THE
STRONGER SLOWER PATTERN BUT CURRENT MAJORITY FASTER AND LESS
AMPLIFIED. TOOK TEMPS A FEW DEGREES COLDER THAN GUIDANCE WED THRU
FRI...AND WILL NOTE THE POTENTIAL FOR MUCH COLDER TEMPS IF MORE
AMPLIFIED SOLUTIONS VERIFY. 67

&&

.AVIATION...

PRESSURE GRADIENT WILL REMAIN CONSTANT TONIGHT INTO SATURDAY AT TAF 
SITES.  THUS...SOUTH TO SOUTHWEST WINDS TO DIMINISH THIS EVENING AND 
THEN GRADUALLY PICK UP AGAIN SATURDAY MORNING. VFR THROUGH THE 
PERIOD WITH ONLY A FEW CIRRUS EXPECTED.

&&

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

&&

$$