[LeArc] Forecast Discussion : MLI@ 6/11/2003 3:22:36 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 112013
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
312 PM CDT WED JUN 11 2003

NEARLY 20 DEGREE F TEMPERATURE GRADIENT ACROSS FORECAST AREA THIS 
AFTERNOON DUE TO LAKE ENHANCED FRONT BISECTING AREA FROM SW TO NE. 
AT 18Z...STRATUS AND TEMPERATURES IN 60S WERE NORTH OF FRONT WHICH 
WAS FROM JUST NORTHEAST OF KCID...ARCHING SOUTH OF QUAD CITIES TO 
JUST NORTH OF KPIA. SOUTHEAST OF FRONT...AIRMASS MORE UNSTABLE WITH 
TEMPS IN 70S...DEW POINTS CLOSE TO 70 AND PARTIAL SUNSHINE. 
MEANWHILE...MAIN SYNOPTIC FRONT THAT PUSHED THROUGH OVERNIGHT WAS 
NOT TOO FAR AWAY...FROM ABOUT KDTW THROUGH CENTRAL IL TO NORTHEAST 
MO MARKED BY TSRA IN W CENTRAL IL. FEW SHOWERS EARLY THIS AFTERNOON 
TRIED TO FIRE ALONG LAKE NORTHERN FRONT...BUT WERE SHORT LIVED. 
FORECAST CHALLENGE CONTINUES TO BE TSRA CHANCES THROUGH 7 DAYS WITH 
MODELS CONTINUING TO STRUGGLE WITH CONTINUITY AND POOR AGREEMENT ON 
WEAK SYNOPTIC FEATURES TO IMPACT AREA THROUGHOUT FORECAST.

MOST CONVECTION WILL REMAIN SOUTHEAST OF FORECAST AREA THIS EVENING 
ALONG MAIN FRONT. HOWEVER...WITH WEAK UPPER FORCING FROM INCREASING 
UPPER DIVERGENCE AND H5 LOW OVER S CENTRAL MO BRUSHING BY TO 
SOUTHEAST COMBINED WITH LI/S JUST BELOW ZERO IN FAR SOUTH AND 
AFOREMENTIONED GREAT LAKES FRONT IN AREA...WILL KEEP SLIGHT CHANCE 
GOING FOR EVENING PERIOD. WIDESPREAD STRATUS DECK SHOWING SOME SIGNS 
OF RETREATING THIS AFTERNOON...BUT THINK IT SHOULD HANG ON IF NOT 
PUSH BACK SOUTHWEST SOME OVERNIGHT TO KEEP TEMPERATURES FROM 
FALLING  MUCH OVER NW IL INTO EASTERN IA. 

ALL MODELS DEVELOP A SEPARATE VORT MAX/SHORT WAVE OVER CENTRAL NEB 
BY THURSDAY MORNING THAT IS ALONG FAR SOUTHERN TAIL OF STRONGER WAVE 
CURRENTLY MOVING INTO EASTERN MT. GFS IS STRONGEST WITH THIS 
FEATURE...AND BASED ON CONVECTION THAT FIRED LATE MORNING ALONG 
WY/CO BORDER LOOKS TO BE REAL...WITH PERHAPS SOME CONVECTIVE 
FEEDBACK ISSUES. THIS FEATURE WOULD PUSH INTO EASTERN IA LATE 
THURSDAY AFTERNOON OR EVENING. BASED ON PROGGED H85 FRONT LOCATION 
ACROSS NORTHERN MO...ANTICIPATE ANY CONVECTION THAT GETS GOING TO 
AFFECT FAR MAINLY SOUTH. KEPT LATE AFTERNOON CHANCES IN WEST...THEN 
OVERNIGHT ACROSS SOUTH. VERY WEAK SURFACE PRESSURE FIELDS INDICATED 
OVER AREA THURSDAY AND FRIDAY...BUT AGREE WITH PREVIOUS FORECAST 
TRENDS OF MAIN SURFACE FRONT AND BEST LOW LEVEL MOISTURE AND 
INSTABILITY REMAINING TO SOUTH TO INTERACT WITH SOUTHERN 
STREAM...WHILE STRONGER MID AND UPPER LEVEL NORTHERN STREAM FLOW
REMAINS WELL TO NORTH TO LIMIT OUR TSRA CHANCES FRIDAY THROUGH 
FRIDAY NIGHT AND TRIMMED BACK TO FAR SOUTH. LOW CONFIDENCE FOR 
SATURDAY INTO SATURDAY NIGHT AND KEPT TSRA CHANCES GOING OVER ENTIRE 
AREA AS MODELS HAVE POOR AGREEMENT ON UPPER LEVEL FEATURES. WILL GO 
ALONG WITH GFS IDEA OF DEEP EAST TO NORTHEASTERLY FLOW FROM GREAT 
LAKES TO EXCLUDE TSRA CHANCES SUNDAY. BEYOND...KEPT DRY WITH 
ZONAL H5 FLOW ACROSS CANADA AND CUTOFF LOW DEVELOPING WELL TO SOUTH 
KEEPING GULF MOISTURE WELL TO SOUTH. 

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

SHEETS
$$