FXUS63 KSGF 301205
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
605 AM CST MON NOV 30 2009

...UPDATE TO AVIATION...

.DISCUSSION...

A COLD FRONT PASSED OVER THE REGION YESTERDAY ALLOWING A MUCH COOLER 
AIRMASS TO SPREAD IN.  THIS CHANGE IN AIRMASS IN CONJUNCTION WITH 
CLEAR SKIES CAUSED TEMPERATURES TO FALL INTO THE UPPER 20S AND 
LOWER 30S THIS MORNING.  NORTHWEST WINDS RANGED FROM 5 TO 15 MPH 
OVER MUCH OF THE EASTERN PLAINS AND MID MISSOURI RIVER VALLEY REGION.

FOR TODAY...SURFACE HIGH PRESSURE IS EXPECTED TO SHIFT INTO THE DEEP 
SOUTH.  MEANWHILE PARCELS FLOWING OFF OF THIS FEATURE WILL CREATE A 
RETURN OF SOUTH WINDS THIS AFTERNOON.  ALONG WITH MOSTLY SUNNY 
SKIES...WE COULD OBSERVE TEMPERATURES RIGHT BACK INTO THE MID 50S 
OVER THE OSAGE PLAINS.  COOLER READINGS ARE EXPECTED IN THE EASTERN 
OZARKS...AN AREA IN WHICH RETURN FLOW WILL BE DELAYED IN COMPARISON 
TO LOCATIONS OUT WEST.

ANOTHER MILD DAY IS ON TAP FOR TUESDAY.  AS A MATTER OF 
FACT...TEMPERATURES IN THE UPPER 50S TO NEAR 60 CAN NOT BE RULED OUT 
DURING THE AFTERNOON.  SOUTHERLY WINDS WILL CONTINUE ON TUESDAY WITH 
NO CHANCES FOR PRECIPITATION.

MUCH ATTENTION HAS BEEN FOCUSED AROUND AN ONGOING UPPER LEVEL LOW 
PRESSURE SYSTEM THAT CAN BE VIEWED ON THE MOISTURE CHANNEL OVER THE 
BAJA REGIONS.  THIS UPPER LOW WILL EVENTUALLY PROGRESS 
EASTWARD...LIKELY TO PRODUCE CLUSTERS OF DEEP CONVECTION OVER AREAS 
OF THE DEEP SOUTH.  UNCERTAINTY HAS EXISTED ON WHETHER THIS LOW WILL 
TRACK FAR ENOUGH NORTH TO CREATE SOME LIGHT RAIN OR EVEN A BAND OF 
NON-ACCUMULATING SNOW OVER SOUTHERN MISSOURI.  

THE GFS AND ECMWF HAVE TRENDED THE TRACK OF THIS LOW FURTHER 
NORTH...CERTAINLY INCREASING THE CHANCES FOR AN EPISODE OF LIGHT 
RAIN OVER THE SOUTHERN OZARKS DURING THE DAY ON 
WEDNESDAY...POTENTIALLY CHANGING OVER TO A BRIEF PERIOD OF SNOW.  
SOME OF THIS ACTIVITY COULD LINGER INTO WEDNESDAY NIGHT.  THERE ARE 
NUMEROUS NEGATIVES THAT WOULD MITIGATE SNOW ACCUMULATION.  

1: GROUND TEMPERATURES ARE STILL IN THE 40S.
2: SURFACE TEMPS ON WED ARE EXPECTED IN THE UPPER 30S TO NEAR 40.
3: THE UPPER LOW IS VERY PROGRESSIVE AND LIFTS OUT WED EVENING.
4: DEEP SOUTH CONVECTION WILL ROBB MOISTURE ADVECTION INTO THE OZARKS.
5: SNOWFALL DURING THE DAYTIME SOMETIMES HAS DIFFICULTY ACCUMULATING.

HEADING INTO THURSDAY AND FRIDAY...THE UPPER PATTERN BECOMES HIGHLY 
AMPLIFIED...WITH LONG WAVE TROUGHING DIRECTED INTO THE NATIONS 
MIDSECTION.  THIS WILL CREATE A PIPELINE OF AIRFLOW FROM SOUTHERN 
CANADA INTO EASTERN KANSAS AND ALL OF MISSOURI.  TEMPERATURES ON 
THURSDAY AFTERNOON WILL STRUGGLE TO WARM OUT OF THE 30S.  WHILE 
SLIGHTLY WARMER AIR IS POSSIBLE ON FRIDAY...AS WESTERLY 
TRAJECTORIES COMMENCE UNDER THE INFLECTION OF THE EASTERN TROUGH 
AND WESTERN RIDGE.

CRAMER

&&

.AVIATION...

FOR THE 30/1200Z KSGF/KJLN/KBBG TAFS...SOME AREAS OF MVFR FOG
DEVELOPED OVER WESTERN MO WHERE LIGHT/CALM WINDS EXIST. ANY LIGHT
FOG WILL BURN OFF QUICKLY THIS MORNING LEAVING VFR CONDITIONS FOR
THE REST OF THE TAF PERIOD. A SFC RIDGE WILL MOVE SOUTHEAST
THROUGH THE AREA TODAY WITH LIGHT WINDS GRADUALLY BACKING TO THE
SOUTH-SOUTHWEST BY MID TO LATE AFTERNOON/21Z-00Z.  DSA

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$