[LeArc] Forecast Discussion : MLI@ 6/22/2003 3:03:15 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 222000
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
300 PM CDT SUN JUN 22 2003

SYNOPSIS-
ACTIVE WEATHER PATTERN IS NOW UNDERWAY ACROSS THE NATIONS MID 
SECTION...WITH TROPICAL MOISTURE AND HEAT PROVIDING SEVERAL CHANCES 
OF STRONG TO SEVERE STORMS THIS WEEK. THIS MORNING...TROPICAL 
MOISTURE HAS MOVED NORTH TO WESTERN IOWA ON LLJ AXIS...NOTED BY 
850MB DEWPOINTS OF 17C AT OAX 12Z.  PLENTY OF CONVECTION IS FIRING 
IN THIS MOIST AXIS...BORDERED TO THE WEST BY A MID LEVEL WARM AIR 
CAP. THIS "CAP OF THE DAY" IS MOST CLOSELY ALIGNED ALONG THE 10C 
700MB TEMP CONTOUR FROM NORTHEAST NEBRASKA TO SOUTHEAST KANSAS. 
ALOFT...SEVERAL MID LEVEL SHORT WAVE TROFS ARE MOVING ACROSS THE 
REGION.  ONE IS LOCATED AT 12Z OVER WESTERN IOWA.  THE NEXT UPSTREAM 
IS LOCATED OVER CENTRAL COLORADO AT 15Z.  THIS TROF HAS A 60KT 500MB 
JET STREAK ASSOCIATED WITH IT...AND GOOD DRYING BEHIND IT ON WATER 
VAPOR SAT. 

SHORT TERM...(TONIGHT THRU TUESDAY AFTERNOON)
NEITHER HIGHER RESOLUTION SHORT TERM MODEL (ETA/GFS) IS DOING VERY 
WELL WITH THE ONGOING STRONG CONVECTION ACROSS THE WESTERN HALF OF 
IOWA TO NORTHEAST KANSAS.  IRONICALLY...THE NGM IS DOING QUITE 
WELL...AND HAS BY FAR THE BEST QPF FIELDS THROUGH 00Z MONDAY. THIS 
IS QUITE DISCOURAGING AS MESOSCALE BOUNDARIES WILL PLAY A VERY 
IMPORTANT ROLE IN THE NEXT 36 HOURS AS TO WHERE STRONG CONVECTION 
WILL DEVELOP AND TRACK. A LOOK AT THE PREVIOUSLY MENTIONED "CAP OF 
THE DAY" 700MB TEMP...EASTERN IOWA REMAINS SLIGHTLY NORTH AND EAST 
OF THIS LEVEL THROUGH MID DAY TUESDAY.  WE FELL THAT A BROKEN 
LINE/AREA OF CONVECTION WILL SLIDE EAST SOUTHEAST TONIGHT AS A WELL 
DEFINED SHORT WAVE MOVES ACROSS THE AREA.  LATE NIGHT/EARLY MORNING 
TIMING WILL LIKELY LIMIT INSTABILITY AND ANY WIDESPREAD SEVERE 
THREAT. HOWEVER...AN OUTFLOW BOUNDARY FROM TONIGHTS ACTIVITY IS 
LIKELY TO LAY DOWN IN THE CENTRAL OR SOUTHERN CWA MONDAY.  THIS MAY 
BE THE FOCUS FOR STRONG TO SEVERE STORMS MONDAY AFTERNOON IF THEY 
CAN BREAK THE CAP.  WILL LEAVE IN CHANCE POPS MONDAY NIGHT AND EARLY 
TUESDAY AS THERE WILL BE THE POTENTIAL FOR ANOTHER DECAYING MCS 
MOVING IN.  SEVERE POTENTIAL FOR DAMAGING WIND MAY EXIST DURING THIS 
PERIOD IF MID LEVEL CAPPING IS LESS THAN LATEST 12Z MODELS 
SUGGEST.   
ERVIN...

WEDNESDAY THROUGH SUNDAY...

WEDNESDAY AND THURSDAY IS THE TIME FRAME IN WHICH THE FRONT WILL 
FINALLY PASS THROUGH THE AREA.  FOR NOW...IT APPEARS THAT EARLY 
WEDNESDAY CONDITIONS WILL FAVOR KEEPING ACTIVITY TO THE WEST AND 
NORTH...BUT WILL MOVE TO OVER CENTRAL AND WESTERN CWA BY 
AFTERNOON...AND WILL AFFECT THE ENTIRE CWA AS THE FRONT MOVES IN.  
CURRENT THINKING IS TO BRING THE FRONT THROUGH CWA LATE WEDNESDAY 
NIGHT AND EARLY THURSDAY MORNING...WITH PRECIPITATION ALONG AND 
AHEAD OF THE FRONT.  PRECIP SHOULD DRY OUT PRETTY QUICKLY 
IMMEDIATELY BEHIND THE FRONT...BUT WITH THE UPPER LEVEL LOW NOT 
MOVING THROUGH UNTIL FRIDAY...HAVE HUNG ON TO LOW CHANCE POPS FOR 
THURSDAY NIGHT AND FRIDAY.  CAN FINALLY GO DRY BY FRIDAY NIGHT.  
BEHIND FRONT WOULD BE VERY TEMPTING TO GO QUITE COOL...BUT THIS HIGH 
WILL NOT BE NEARLY AS STRONG AS THIS LAST EVENT...AND HIGHS REACHED 
INTO THE UPPER 70S TO LOW 80S THE DAY AFTER THE FRONT MOVED 
THROUGH...SO WENT WARMER THAN GUIDANCE FOR THURSDAY THROUGH SATURDAY.

SATURDAY AND SUNDAY TO BE THE ONLY REAL DRY DAYS OUT OF THE WHOLE 
FORECAST...WITH THE UPPER LEVEL LOW FINALLY MOVING OFF TO THE 
EAST...AND SHORTWAVE RIDGING BUILDING IN.  WE THEN TRANSITION TO 
ZONAL FLOW ON THE GFS FOR SUNDAY.  SURFACE SOUTHWEST FLOW 
RE-ESTABLISHES ITSELF FOR SUNDAY...AND TEMPS OUGHT TO TREND BACK 
TOWARDS WARMER THAN NORMAL.  
LE...

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

$$