[LeArc] Forecast Discussion : MLI@ 6/26/2003 3:56:29 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 262047
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
345 PM CDT THU JUN 26 2003

STRONG EARLY SUMMER MID LEVEL TROUGH OVER MANITOBA ON THIS MORNING 
UA ANALYSIS. H250 12HR HGT FALLS OF 290M AT INL IMPRESSIVE FOR LATE 
JUNE.  SURFACE FRONT ASSOCIATED WITH SYSTEM STRETCHED FROM LOW 
PRESSURE OVER ONTARIO THROUGH MI THEN SW THROUGH THE LOWER OHIO 
VALLEY.  WRAP AROUND SC STAYED NORTH OF CWA TODAY WITH MAINLY SCT 
CU OVER THE MID MS VALLEY.

MAIN FORECAST CONCERNS IN THE SHORT TERM WILL BE TEMPS TONIGHT. 
ATTENTION LATER IN THE FCST PERIOD TURNS TO PCPN CHANCES OVER THE 
WEEKEND.  

NO SIGNIFICANT INITIALIZATION PROBLEMS WERE NOTED THIS MORNING AND 
MODEL SOLUTIONS WERE SIMILAR THROUGH THE PERIOD.  THERE WERE SOME 
DISCREPENCIES BETWEEN THE GFS AND ETA ON THE SYSTEM PROGGED TO MOVE 
ACROSS N CENTRAL U.S. FRIDAY NIGHT AND SATURDAY WITH THE AVN A 
LITTLE STRONGER AND FURTHER NORTH WITH THE SURFACE SYSTEM THAN THE 
ETA DEPICTS.  FOR TONIGHT...SKIES SHOULD CLEAR EARLY THIS EVENING 
WITH LOSS OF HEATING.  UPSTREAM SURFACE DEWPOINTS IN THE MID/UPPER 
40S THIS AFTERNOON WOULD SUPPORT NEAR RECORD TEMPS FOR FRIDAY 
MORNING.  HOWEVER...EXPECT TO KEEP SOME WIND GOING THROUGH THE NIGHT 
WITH LITTLE RELAXATION IN THE SURFACE PRESSURE GRADIENT. CURRENT 
FORECAST REFLECTS THIS THINKING AND WILL NOT MAKE ANY SIGNIFICANT 
CHANGES.  DRY WX TO CONTINUE THROUGH THE DAY FRIDAY AS A WEAK 
SURFACE TROUGH APPROACHES FROM THE NW.  SW FLOW AHEAD OF THE TROF 
SHOULD PROVIDE SOME GOOD MIXING AND WILL FAVOR THE WARMER FWC/MET 
TEMPS.  SYSTEM DROPPING DOWN OUT OF THE NORTHERN PLAINS FRIDAY NIGHT 
AND SATURDAY WILL RETURN THE THREAT OF PCPN TO THE REGION.  THERE IS 
SOME DISCREPENCY IN THE PLACEMENT OF THE WARM FRONT EARLY SATURDAY 
WITH ETA HOLDING THE FRONT OVER NE IA AND NRN IL WHILE GFS KEEPS 
OVER SRN MN/CENTRAL WI.  CURRENT FORECAST ALREADY HAS LOW POPS 
ACROSS THE NORTH FOR LATE FRIDAY NIGHT AND WILL LEAVE IN PLACE.  
HOWEVER...CHANGED WORDING FROM SHRA TO TSRA BASED ON MID LEVEL LAPSE 
RATES AND POTENTIAL FORCING.  TIMING ISSUES CONTINUE WITH FRONT PROGGED
THROUGH REGION SATURDAY NIGHT.  WILL KEEP LOW POPS SATURDAY CWA 
WIDE...BUT BEST THREAT APPEARS TO BE JUST AHEAD OF THE 
BOUNDARY...DURING THE EVENING HOURS.   WILL HOLD ON TO LOW POPS 
SUNDAY IN THE SOUTH WITH FRONT STALLING ACROSS NRN MO.  THEN DRY WX 
FOR THE CWA INTO MONDAY WITH HIGH PRESSUE DOMINATING REGION.

IN THE EXTENDED GFS AND EUROPEAN MODELS ARE HANDLING MID WEEK NW 
FLOW DIFFERENTLY.  THE EUROPEAN MODELS ARE MORE ENERGETIC WITH THE 
MID LEVEL FLOW OVER NRN U.S. WHILE GFS BUILDS MORE MID LEVEL RIDGING 
OVER THE REGION...SUGGESTING DRY WX. WILL MAINTAIN CHANCE POPS 
ALREADY IN FORECAST FOR TUES NIGHT AND INTRODUCE POPS FOR THURSDAY 
PER GFS MOVING FRONT INTO NRN IA BY THURSDAY AFTERNOON.

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

$$

DLF