306 
FXUS63 KTOP 061137
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
537 AM CST SUN JAN 6 2013

...UPDATE TO AVIATION...

.DISCUSSION...

UPPER TROUGH MOVE OFF TO THE EAST INTO THE GREAT LAKES AND OHIO 
VALLEY AT 08Z. FURTHER WEST A RIDGE WAS BUILDING INTO THE ROCKIES 
AHEAD OF AN UPPER LOW MOVING INTO CALIFORNIA FROM THE EASTERN 
PACIFIC. 

AREA OF STRATUS CLOUDS WILL MOVE ACROSS THE NORTHEAST CORNER OF 
NORTHEAST KANSAS EARLY THIS MORNING WITH SUNNY SKIES EXPECTED FOR 
THE REST OF THE DAY. SHOULD MIX DOWN FROM ABOUT 925 MB THIS 
AFTERNOON WHICH WILL YIELD HIGHS AROUND 40 FOR MOST AREAS EXCEPT FOR 
THE DEEPER SNOW COVER IN NORTH CENTRAL KANSAS WHERE HIGHS WILL 
REMAIN IN THE 30S.

THE UPPER TROUGH WILL MOVE INTO THE SOUTHWEST TONIGHT WITH A 
DEVELOPING LEE SIDE TROUGH. SURFACE HIGH WILL MOVE OFF TO THE EAST 
AFTER 06Z WITH SOUTHERLY WINDS KICKING IN. LOWS TONIGHT IN THE LOW 
TO MID 30S.

MODELS HAVE COME INTO BETTER AGREEMENT WITH THE PROGRESSION OF THE 
UPPER LOW MOVING OUT OF THE SOUTHWEST AND INTO THE SOUTHERN PLAINS 
WEDNESDAY THROUGH THURSDAY. TEMPERATURE PROFILES INDICATE 
PRECIPITATION SHOULD MOSTLY BE LIQUID THROUGHOUT THE EVENT...SAVE 
FOR A MIX IN THE NORTH CENTRAL COUNTIES WEDNESDAY NIGHT OF RAIN AND 
SNOW. TEMPERATURES WILL BE ABOVE NORMAL MONDAY THROUGH FRIDAY WITH
HIGHS IN THE 40S.

MODEL DISCREPANCIES STICK OUT AT THE END OF THE PERIOD NEXT SATURDAY 
WITH THE UPPER TROUGH DIGGING INTO THE SOUTHWEST BETWEEN THE 
ECMWF/GFS AND GFS ENSEMBLE FORECASTS. THUS CONFIDENCE IN PROBABILITY 
OF PRECIPITATION IS LOW. HAVE THEREFORE CUT BACK ON PRECIPITATION 
CHANCES ON SATURDAY. AS THIS SYSTEM MOVES ONSHORE LATER THIS WEEK 
MODELS WILL LIKELY IMPROVE THEIR HANDLING OF THE SYNOPTIC FEATURES.

53

&&

.AVIATION...

VFR CONDITIONS ANTICIPATED. SURFACE RIDGE PASSING THROUGH WILL
BRING NORTHWEST WINDS EARLY AND BACK TO SOUTHERLY BY 22Z. STRONG
INVERSION DEVELOPING AFTER 0Z COULD LEAD TO LLWS AND THIS WILL BE
MONITORED.

65

&&

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

$$