[LeArc] Forecast Discussion : MLI@ 6/9/2003 3:33:45 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 090831
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
330 AM CDT MON JUN 9 2003

EARLY MORNING SURFACE ANALYSIS SHOWED REGION BETWEEN SURFACE LOW 
JUST NORHT OF LK HURON AND WEAK SURFACE RIDGE OVER THE MO RIVER 
VALLEY.  00Z H5 ANALYSIS SHOWED BROAD WNW FLOW OVER THE WESTERN HALF 
THE U.S.  THE H5 LOW THAT BOUGHT THE RAINS TO THE MID MISSISSIPPI 
VALLEY WAS OVER NRN LAKE MICHIGAN. NEXT WAVE TO IMPACT REGION 
EXTENDED FROM EASTERN WASHINGTON INTO SOUTHERN ALBERTA.  

MODELS INITIALIZED FAIRLY WELL TONIGHT.  AT LEAST THROUGH THE FIRST 
24 HOURS MODELS WERE IN GOOD AGREEMENT AND WERE NOW SHOWING SIMILAR 
SOLUTIONS WITH RESPECT TO THE SURFACE LOW DEVELOPING OVER THE PLAINS 
THIS AFTERNOON.  MODELS ALL SHOW THE LOW LIFTNING ENE AND DEEPENING 
AS IT MOVE THROUGH SOUTHERN MN INTO NRN WISCONSIN TONIGHT AND 
TUESDAY MORNING.   MAIN FORECAST CHALLENGE THIS MORNING WILL BE THE 
IMPACT THE LOW PRESSURE SYSTEM HAS ON REGION TONIGHT.

QUIET WEATHER WILL BE THE RULE TODAY WITH WEAK SURFACE RIDGE 
TRAVERSING CWA.  BASED ON MOIST H7 WNW FLOW OVER REGION WILL 
PROBABLY SEE SOME PATCHY AC DURING THE DAY ESPECIALLY OVER THE 
NORTHEASTERN CWA.  WITH THE CLOUD POTENTIAL WILL KEEP TEMPS TODAY 
JUST UNDER THE WARMER MET GUIDANCE...ABOUT THE SAME AS GOING 
FORECAST.  THUNDERSTORM POTENTIAL STILL LOOKS GOOD TONIGHT.  BEST 
THREAT WILL BE TO OUR NORTH AHEAD OF SURFACE LOW.  MODELS SHOW THETA 
E RIDGE INPLACE OVER ERN NEBRASKA AT 00Z.  RIDGE SHIFTS INTO WESTERN 
IOWA BY 06Z AS LOW LEVEL JET VEERS TO THE SOUTHWEST AND PLACES ERN 
IA IN REGION OF STRONG THETA E ADVECTION.  ALL THIS IS COINCIDENT 
WITH MID LEVEL SHORT WAVE MOVING ACROSS REGION.  CURRENT FORECAST 
HAS MENTION OF CONVECTION AFTER 03Z...WHICH STILL LOOKS GOOD.  BEST 
THREAT THOUGH WILL BE AFTER 06Z WITH STRONGEST MID LEVEL FORCING 
COMING INTO  PLAY. AGREE WITH DMX ASSESMENT THAT BY THE TIME 
CONVECTION GETS GOING OVER EASTERN IOWA...IT SHOULD BE ELEVATED.  
FORECAST SOUNDINGS SHOW WBZ HEIGHTS WILL BE JUST OVER 9K FT BY 
06Z...SO LARGE HAIL WILL BE THE MAIN SEVERE WEATHER THREAT.  
RAINFALL AMOUNTS WILL ALSO BE OF SOME CONCERN WITH LLJ FEEDING OFF 
REGION OF PW'S NEAR 1.5 IN OVER WESTERN IOWA. THE HIGH PW'S SUGGEST 
THAT AN INCH OR BETTER QPF IS POSSIBLE OVER CWA. HOWEVER WITHOUT A 
LOW LEVEL BOUNDARY TO FOCUS HEAVIER PCPN...THE HIGHER AMOUNTS SHOULD 
BE THE EXCEPTION.  MODELS ARE IN GOOD AGREEMENT MOVING FRONT THROUGH 
CWA TUESDAY AFTERNOON.  MODELS...ESPECIALLY THE ETA...SUGGEST THAT 
THERE WILL BE ANOTHER SEVERE WEATHER THREAT AHEAD OF THIS FRONT 
ALONG AND EAST OF THE MISSISSIPPI RIVER. TIMING OF THE FRONT IS 
FAVORABLE...BUT MODELS ARE SHOWING CONVERGENCE ALONG THE BOUNDARY 
WILL BE WEAK.  BOUANCY AHEAD OF THE FRONT IS ALSO QUESTIONABLE.  AT 
THIS POINT IT LOOKS LIKE THE ETA MAY BE OVERDOING THE TEMPS/CAPES 
FOR TUESDAY. GFS IS SHOWING A LOT MORE RH IN THE LOW LEVELS AND 
THEREFORE IS HOLDING DOWN TEMPS MORE.  MODELS ARE ALL PUSHING FRONT 
AT LEAST INTO CENTRAL MO TUESDAY NIGHT.  THIS SHOULD KEEP THE ACTIVE 
WEATHER SOUTH OF THE CWA THROUGH MID WEEK. GFS WAS SETTING UP A 
MODERATE NORTHEAST SURFACE FLOW OVER CWA WEDNESDAY AND THURSDAY. AS 
A RESULT HAVE BACKED OFF TEMPS ABOUT A CATEGORY FROM PREVIOUS 
FORECAST.  

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

$$
DLF