[LeArc] Forecast Discussion : MLI@ 2/28/03 1:53:50 PM

[learc@mailman.qth.net]

The following weather message is provided by McDonough County E.S.D.A.


FXUS63 KDVN 282002
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
200 PM CST FRI FEB 28 2003

.OVERVIEW...WEAK SERIES OF UPPER AIR ENERGY PULSES IN SOUTHERN
PLAINS SLIDING TOWARD FORECAST AREA.  LOCAL RADARS REVEAL FLURRIES
AND LIGHT SNOW IN SOUTHERN PLAINS WITH GENERAL COVERAGE BEST HANDLED
BY GFS-AVN AND UKMET.  CLOUDS INCREASING ACROSS AREA IN ADVANCE OF
DISTURBANCES. UPPER AIR ANALYSIS SUPPORT LIMITED FORCING AND MOISTURE
FOR ANYTHING BUT A LIGHT EVENT TONIGHT BUT WEAK OVERRUNNING TO
CONTINUE INTO MID DAY SATURDAY.  RADAR MOVEMENT AND AWIPS DISTANCE
TIME FEATURE SUGGESTS LEADING EDGE OF SNOW TO ARRIVE BY MID EVENING.
IN SW SECTIONS.   UPPER AIR SUPPORTS VIGOROUS SHORT WAVE IN BC TO
DIVE SOUTHEAST AND AFFECT AREA SUNDAY WITH ANOTHER SHOT OF VERY COLD
AIR.

...POPS CHANCES TONIGHT AND EARLY SATURDAY...THEN COOL-DOWN SUNDAY
WITH ARCTIC FRONT AND POTENTIAL SIGNIFICANT SYSTEM ON TUESDAY
FORECAST ISSUES...

.DIAGNOSIS AND DAYS 1-3...WILL USE RADAR TRENDS AND UPPER FORCING
FROM UKMET AND GFS-AVN AS THEY ARE SIMILAR FOR POPS AND RH WITH
MINOR INPUTS FROM ETA.  THUS...AS PRIOR SHIFT WELL STATED...FLURRIES
AND SOME LIGHT SNOW TO AFFECT AREA TONIGHT INTO MID DAY SATURDAY WITH
MINOR ACCUMULATIONS POSSIBLE.  BEST FORCING ALONG AND SOUTH OF
HIGHWAY 34...WILL KEEP HIGHEST POPS THERE WITH ACCUMULATIONS LESS
THAN ONE INCH WHERE LIKELY WORDING NEEDED.  LOWS WILL GO 1-2
CATEGORIES ABOVE BASED ON SOUTH WIND AND LOW CLOUDS WITH POPS.
TOMORROW...LOW CLOUDS AND CHANCE OF FLURRIES MOST AREAS EXCEPT FAR NW
INTO MID AFTERNOON WITH CHANCE OF LINGERING MORNING LIGHT SNOW SE
SECTIONS.  HIGHS WILL TREND NEAR GUIDANCE BLEND AND EVEN A COUPLE
DEGREES BELOW DUE TO LOTS OF CLOUDS.  SATURDAY NIGHT KEEP CLOUDS WITH
FLURRIES LATE WITH NEXT ARCTIC INTRUSION NW SECTION TOWARD MORNING ON
GUSTY NW WINDS OF 15 TO 25 MPH....MOST AREAS LOWS TO SLIGHTLY ABOVE
GUIDANCE. SUNDAY...NEAR STEADY TEMPS AND INTENSE CAA BATTLING EARLY
MARCH SUNSHINE...THERMAL PARCELS SUPPORT FLURRIES EVEN INTO PM DUE TO
INTENSE MIXING...SIMILAR TO MONDAY AM WHICH MODEL DON/T-CAN/T HANDLE.
EVEN CHANCE FOR SOME SNOW SHOWERS IF DEWPOINTS ARE A FEW DEGREES
HIGHER TO PASS TP LATER SHIFTS TO CONSIDER.  SUNDAY NIGHT LOWS TO BE
AROUND OR JUST AFTER MIDNIGHT AND WILL LOWER ACCORDINGLY 1-2
CATEGORIES BEFORE SOME CLOUDS AND WAA KICKS IN.  MONDAY WEAK WARM
FRONT TO AFFECT AREA AS JET REDEVELOPS FURTHER NORTH IN ADVANCE OF
NEXT SHORT WAVE OUT OF CANADA WITH CHANCE POPS ALONG HIGHWAY 20 AND
SIGNIFICANT WARMUP SOUTH AREAS ON BREEZY SW WINDS.

.EXTENDED (TUE-FRI)...GFS-AVN MOST PROLIFIC BUT ETA AND UKMET ALSO
SUPPORTS STRONG JET AND BAROCLINICITY OVER AREA TUESDAY WITH VIGOROUS
SHORT WAVE SUPPORTING LIKELY POPS MOST AREAS.  MAKE MINOR UPDATES OF
HWO FOR THIS SYSTEM FOR INCREASED CONFIDENCE AND SOME ACCUMULATIONS
POSSIBLE.   THEN ANOTHER SHOT OF ARCTIC AIR FROM CANADA...WILL TREND
ON LOWER SIDE OF MEX/FMR AND MORE IN LINE WITH GFS-AVN LOW LEVEL
THERMAL FIELDS INTO WEDNESDAY...THEN DECENT WARMUP THURSDAY AHEAD OF
NEXT SYSTEM LATE NEXT WEEK.

.DVN...
IA...NONE.
IL...NONE.
MO...NONE.

$$

NICHOLS