[LeArc] Forecast Discussion : MLI@ 3/29/2003 3:30:05 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 290926
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
326 AM CST SAT MAR 29 2003

CYCLONIC FLOW AROUND SURFACE LOW MOVING EAST OUT OF ONTARIO TO 
CONTINUE GRADUALLY WEAKEN TODAY. AT UPPER LEVELS...TROUGH AXIS OVER 
EASTERN NEB AT 00Z TO SLIDE EAST ACROSS AREA. SHORT TERM FORECAST 
CHALLENGES MAINLY TEMPERATURES AND CHANCE FOR SHOWERS TODAY.

VORT LOBE EVIDENT ON WATER VAPOR IMAGERY WITH ACCOMPANYING BANDS OF 
SNOW SEEN ROTATING INTO NORTHWEST MO AT 08Z. MODELS SLIDE THIS EAST 
THEN NORTHEAST ACROSS FAR SOUTHERN CWFA THIS MORNING. MAIN TROUGH 
AXIS PUSHES ACROSS MISS RIVER AROUND 18Z...THEN ONLY CHANNELED 
VORTICITY WELL TO SOUTHWEST ON BACKSIDE OF TROUGH IN AFTERNOON. 
LAPSE RATES STEEPEN HOWEVER AS H5 COLD POOL MOVES INTO EASTERN IA BY 
AFTERNOON. BEST CHANCE FOR SHOWERS APPEARS IN SOUTHWEST ZONES...WERE 
LARGE CLEARING EARLY THIS MORNING MAY PERMIT SOME EARLY BUT BRIEF 
SUNSHINE BEFORE INSTABILITY CU FILL IN. META H85-H7 AND H7-H5 LAPSE 
RATES EXCEED 7 C/KM IN THIS AREA AND THUS INTRODUCED 30 POPS FOR 
SHOWERS. THERMAL PROFILES SUGGEST MAINLY SNOW...BUT WITH SURFACE 
TEMPERATURES APPROACHING 40...WILL GO WITH MIX OF RAIN AND SNOW WITH 
NO ACCUMULATIONS MENTIONED. RAISED CENTRAL ZONES TO SLIGHT CHANCE 
WORDING...WHERE THERE WILL BE MORE CLOUDS AND WEAKER FORCING. ANY 
CONVECTION WILL END BY EVENING OR SHIFT EAST OF AREA WITH UPPER 
TROUGH AXIS. 

ANY HOLES IN CLOUD COVER SHOULD RAPIDLY FILL IN TODAY WITH THERMAL 
TROUGH OVERHEAD. CLOUDS AND LOW LEVEL COLD AIR ADVECTION TO KEEP 
TEMPERATURES IN CHECK AND STAYED CLOSEST TO COOLER MAV AND FWC WITH 
UPPER 30S NORTH TO AROUND 40 SOUTH. TONIGHT...WILL CLEAR CLOUDS OUT 
GRADUALLY AS LOW LEVEL FLOW BECOMES ANTICYCLONIC USING GFS/ETA BLEND 
SOLUTION. THUS WENT WITH MAV LOWS IN LOWER 20S. SUNDAY TO BE A BIT 
WARMER...ESPECIALLY IN SOUTH WHERE MOST SUNSHINE EXPECTED. GFS ALONE 
IN INTRODUCING PRECIP CHANCES IN NORTHEAST ZONES SUNDAY AS VORT 
SLIDES DOWN TROUGH INTO GREAT LAKES. WITH RECENT GFS PERFORMANCE... 
WILL GO WITH CONCENSUS AND LEAVE DRY. 

IN EXTENDED...SIGNIFICANT WARMUP AS WESTERN RIDGE MOVES EAST AND 
FLATTENS INTO ZONAL FLOW OVER AREA BY MIDWEEK. HAVE CONTINUED TREND 
OF ON-GOING GRIDS...GOING ABOVE GUIDANCE WITH DEGREE OF WARMING AS
MODELS HAVE CONSISTENTLY HAD POOR HANDLE ON SIMILAR SITUATIONS THE 
PAST COUPLE MONTHS. NEXT SIGNIFICANT CHANCE FOR RAIN IN FRIDAY AND 
SATURDAY TIMEFRAME.  

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

$$

DLS