FXUS63 KSGF 282308
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
508 PM CST SAT NOV 28 2009

...UPDATE TO AVIATION...

.DISCUSSION...

SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)...

CURRENTLY...COLD FRONT IS TAKING SHAPE TO OUR NORTHWEST...
EXTENDING ROUGHLY FROM DSM TO RSL TO JUST NORTHWEST OF DDC. DECENT
PRESSURE GRADIENT STILL ACROSS THE REGION AIDING IN VERY MODEST
LOW LEVEL MOISTURE RETURN. MAIN SENSIBLE WEATHER FEATURES THIS
AFTERNOON ARE SCT CIRRUS ALONG WITH OCCASIONALLY GUSTY WINDS.
TEMPERATURES ARE QUITE PLEASANT WITH READINGS IN THE MIDDLE TO
UPPER 60S AREA WIDE.

TONIGHT...QUIET WEATHER WILL CONTINUE. NORTHERN STREAM TROUGH WILL
BE ON THE MOVE ACROSS THE NORTHERN TIER OF STATES...WHICH WILL
GET THE SFC COLD FRONT MOVING. LOW LEVEL JET WILL GIVE MOISTURE
ADVECTION SOME ASSISTANCE...WHICH MAY MANIFEST ITSELF IN A THIN
STRATUS DECK AROUND DAYBREAK. COMBO OF INCREASED CLOUDS AND
SOUTHERLY WINDS WILL KEEP TEMPERATURES ABOVE AVG TONIGHT...WITH
PERSISTENCE...PLUS A FEW DEGREES OUT EAST...EXPECTED.

SUNDAY AND SUNDAY NIGHT...COLD FRONT WILL SLIDE THROUGH THE AREA
DURING THE MORNING. MOISTURE RETURN IS TAKING A ROUNDABOUT TREK
AROUND SFC HIGH PRESSURE CENTERED ACROSS THE GULF. FRONTOGENESIS
WILL INCREASE THROUGHOUT THE DAY...WITH SCT SHRA DEVELOPING AS THE
DAY PROGRESSES. THE BEST OPPORTUNITY FOR SEEING RAINFALL WILL
LIKELY BE ALONG/SE OF THE I44 CORRIDOR SUNDAY AFTERNOON AND
EVENING. WITH THE UPPER WAVE REMAINING PROGRESSIVE...SO SHALL THE
COLD FRONT WITH PRECIP ENDING SUNDAY NIGHT.

MONDAY MONDAY NIGHT...A MODEST COOL DOWN IS EXPECTED BEHIND THE
FRONT...THOUGH NOTHING UNUSUAL FOR LATE NOVEMBER AS TEMPS ACTUALLY
HOVER NEAR AVG. THE SKY SHOULD CLEAR BY MONDAY MORNING.

LONG TERM...(TUESDAY THROUGH SATURDAY)...

THE FOCUS OF THIS PORTION OF THE FORECAST RESIDES WEDNESDAY THROUGH 
THURSDAY MORNING WITH THE POTENTIAL OF RAIN CHANGING TO SNOW 
WEDNESDAY NIGHT. AT THIS TIME...CONFIDENCE IS HIGH IN REGARDS TO 
RAIN INITIALLY WITH LOW CONFIDENCE IN A CHANGE OVER TO SNOW BASED 
UPON DIFFERING MODEL FORECAST THERMAL PROFILES. CONFIDENCE IN THE 
POTENTIAL CHANGE OVER WILL INCREASE WITH FURTHER MODEL RUNS.

A SOUTHWEST UPPER LEVEL LOW WILL EJECT NORTHEAST AND TRACK THROUGH 
THE SOUTHERN PLAINS AND OZARKS WITH THE ARRIVAL OF AN UPSTREAM 
KICKER IN THE PACIFIC NORTHWEST. WHILE THE ECMWF AND GFS ARE SIMILAR 
WITH THE ARRIVAL OF THE UPPER LOW...THE GFS LIFTS THE LOW THROUGH THE 
SOUTHERN OZARKS QUICKER AND OFFERS A MUCH COLDER THERMAL PROFILE (-6 
DEGREES CELSIUS AT 850 MB) COMPARED TO THE ECMWF (1 DEGREE CELSIUS 
AT 850 MB) WEDNESDAY NIGHT. THE TIMING OF THE ARRIVAL OF THIS COLDER 
AIR ALONG WITH THE POTENTIAL DEVELOPMENT OF A TROWAL WILL BE KEY TO 
ANY SNOW DEVELOPMENT AND ACCUMULATION ACROSS THE OZARKS WEDNESDAY 
NIGHT AND THURSDAY MORNING.

SURFACE HIGH PRESSURE WILL BUILD INTO THE OZARKS THURSDAY INTO 
SATURDAY WITH BELOW NORMAL TEMPERATURES AND DRY WEATHER 
EXPECTED.          

ANGLE

&&

.AVIATION...

THE PRIMARY FLIGHT HAZARDS FOR THE NEXT 24 HOURS WILL BE MVFR 
CEILINGS...LOW LEVEL WIND SHEAR...AND SHIFTING SURFACE WINDS. A COLD 
FRONT WILL SWEEP ACROSS THE AREA DURING THE DAY TOMORROW. AHEAD OF 
THE FRONT...WINDS WILL BE SOUTHERLY WITH AN AREA OF MVFR STRATUS 
DEVELOPING AFTER MIDNIGHT. LOW LEVEL WINDS SHEAR WILL PERSIST TONIGHT 
UNTIL THE SURFACE WINDS SHIFT TO NORTHWESTERLY LATE IN THE MORNING. 
A BRIEF PERIOD OF PRECIPITATION IS POSSIBLE WITH THE FRONTAL PASSAGE 
LASTING AROUND 3 HOURS IN THE LATE MORNING TO EARLY AFTERNOON.

KARDELL

&&

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

$$