[LeArc] Forecast Discussion : MLI@ 7/11/2003 2:34:22 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 110732
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
230 AM CDT FRI JUL 11 2003


SYNOPSIS-
NORTHWEST FLOW HAS ESTABLISHED ITSELF ACROSS THE CORNBELT AND GREAT 
LAKES REGION...AND WILL CONTINUE TODAY. WITH 500MB TEMPERATURES -15 
TO -17C AND 700MB TEMPS JUST BELOW 0C COMING DOWN WITH THE NEXT VORT 
MAX...LAPSE RATES WILL BE QUITE STEEP THIS AFTERNOON. THIS VORT MAX 
IS WELL DEFINED ON WATER VAPOR AS IT DROPS SOUTH OVER WESTERN 
MANITOBA EARLY THIS MORNING. 

SHORT TERM (TODAY THROUGH MONDAY)
WE EXPECT CLOUDS TO DEVELOP QUICKLY BY MID MORNING TODAY...AS 
CONVECTIVE TEMPERATURES ARE IN THE LOW 70S.  PARTLY CLOUDY SKIES 
WILL BECOME MOSTLY CLOUDY OVER THE NORTHEAST HALF BY NOON AS THE 
UPPER DISTURBANCE APPROACHES...AND ISOLATED SHOWERS DEVELOP.  BY MID 
AFTERNOON...STEEP LAPSE RATES...LI/S FROM -2 TO -5...AND ETA 
FORECAST CAPES OF 500 TO 1000J/KG WILL HELP SHOWERS BECOME MORE 
NUMEROUS OVER THE NORTHEAST HALF OF THE AREA.  THUNDERSTORMS WILL BE 
POSSIBLE...BY LACK OF ANY FOCUSING MECHANISM WILL KEEP TSRA ACTIVITY 
ISOLATED.  DUE TO THE COLD AIR ALOFT...SOME STRONGER SHOWERS AND 
STORMS MAY PRODUCE PEA HAIL DURING PEAK HEATING HOURS. ANY ACTIVITY 
SHOULD QUICKLY DIMINISH AROUND SUNSET...WITH MOSTLY CLEAR SKIES 
EXPECTED BY LATE EVENING. 

VERY SIMILAR SITUATION EXPECT SATURDAY...THOUGH WE BELIEVE THE 
EXTENT OF THE SHOWER ACTIVITY WILL BE LESS THAN TODAY.  WILL LEAVE 
INHERITED SLIGHT CHANCES IN FORECAST FOR SATURDAY AFTERNOON.  

AS HIGH PRESSURE MOVE SOUTHEAST SUNDAY...SOUTHWEST FLOW AT THE 
SURFACE WILL TURN THE HEAT ON ONCE AGAIN...THOUGH EXPECT HUMIDITY TO 
REMAIN LOW UNTIL EARLY IN THE WEEK. MONDAY WILL BE VERY WARM WITH 
HIGHS CLIMBING BACK INTO THE UPPER 80S. 
...ERVIN

EXTENDED...
LONG RANGE MODELS STILL DEPICTING ANOTHER STRONG MID SUMMER SYSTEM 
MOVING THROUGH TUESDAY. REGION THEN COMES UNDER THE INFLUENCE OF 
CANADIAN HIGH PRESSURE MOVING THROUGH THE GREAT LAKES.  THERE ARE 
SOME TIMING AND INTENSITY DIFFERENCES BETWEEN THE MODELS. IN 
COMPARISON TO THE GFS...THE UKMET IS FASTER WITH THE SURFACE SYSTEM  
AND DEEPER WITH THE MID LEVEL TROF.  THE 10/12Z RUN OF THE ECMWF 
ALSO SHOWS A STRONGER SYSTEM...BUT TIMING OF THE FROPA IS SIMILAR TO 
THE 11/00Z RUN OF THE GFS.  DUE TO DIFFERENCES AMONG THE MODELS WILL 
LEAVE GOING FORECAST ALONE.  IF THE FASTER AND STRONGER SOLUTION OF 
THE UKMET VERIFIES...THEN GOING TEMPS WILL BE A LITTLE ON THE WARM 
SIDE AND TIMING OF TUESDAYS PCPN WILL NEEDED TO BE ADJUSTED. DLF

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

$$