[LeArc] Forecast Discussion : MLI@ 7/16/02 3:01:54 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 160801 CCA
AFDMLI

AREA FORECAST DISCUSSION...CORRECTED...
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
250 AM CDT TUE JUL 16 2002

CORRECTED MODEL CHOICE ON 850 TEMPS FOR THIS AFTERNOON.

QUIET WEATHER TO CONTINUE FOR ANOTHER DAY...WITH STALLED RIDGE OVER 
CWA...AND WEAK UPPER LEVEL LOW OVER SRN MISSOURI FOR SEASONABLY COOL 
TEMPS AND MOSTLY CLEAR SKIES.  UPPER AIR ANALYSIS INDICATING THAT MAIN 
UPPER LEVEL RIDGE SHIFTING EAST AS A SHORTWAVE OVER CANADA RUNS OVER 
THE TOP OF IT.  THE UPPER LEVEL LOW HAS BEEN FILLING SLOWLY OVER THE 
LAST FEW DAYS...AND WILL CONTINUE TO DO SO WITH RISES ALL AROUND IT. 
PATCHY FOG DEVELOPING EARLIER THIS MORNING THAN ON PREVIOUS 3 
MORNINGS...WHICH IS ANOTHER INDICATION OF HOW THE DEWPOINTS HAVE 
BEEN INCREASING OVER LAST FEW DAYS.

PROBLEMS THIS MORNING INCLUDE POPS AS UPPER LEVEL LOW APPROACHES 
...AND TEMPS AS WAA GETS GOING AHEAD OF NEXT SYSTEM.  

00Z MODELS APPEAR TO HAVE INITIALIZED WELL...AND HAVE GOOD 
CONTINUITY TO THEMSELVES WITH THE WEAK UPPER LEVEL LOW...AND ALL ARE 
TREDING A LITTLE FARTHER SOUTH WITH THE UPPER LOW THAN ON PREVIOUS 
RUNS.  THE AVN IS FARTHEST NORTH...AND SEEMS TO BE HANDLING DEPTH OF 
IT THE BEST.  IN GENERAL...MODELS APPEAR TO BE FILLING IT TOO 
FAST...THOUGH AVN PERHAPS DOING THE BEST WITH THIS.  HAVE SOME 
CONCERNS ABOUT THE FRONT APPROACHING THE AREA ON THURSDAY-  NEW RUNS 
APPEAR TO BE SIGNIFICANTLY FARTHER NORTH THAN ON PREVIOUS 
RUNS...KEEPING THE FRONT TO THE NORTH OF THE CWA RATHER THAN ON TOP 
OF...OR JUST SOUTH OF IT.  IN GENERAL...PREFER THE AVN HANDLING OF 
THE UPPER LEVEL LOW...STRONGER...AND FURTHER NORTH.  ETA HAS BETTER 
HANDLE ON CURRENT SURFACE FEATURES.

TODAY AND TONIGHT...ALONG WITH THE CONCERN THAT THE MODELS ARE FILLING THE 
UPPER LOW TOO FAST COMES THE CONCERN THAT THEY ARE ALSO 
UNDERESTIMATING THE STRENGTH OF THE VORT MAX. AGAIN...THE AVN SEEMS 
TO HAVE BEEN DOING THE BEST WITH THIS OVER LAST FEW DAYS AND PREFER 
ITS STRONGER SOLUTION.  AFTERNOON/EVENING PRECIP POSSIBLE ONLY 
IN THE FAR SOUTH...AND DUE TO MOISTURE CONCERNS...WILL KEEP TO 
ISOLATED POPS. INCREASING SOUTHERLY FLOW AND INCREASED CLOUDS SHOULD 
KEEP FOG FROM FORMING MOST AREAS. PERSISTENCE MAY WORK WELL WITH 
TEMPS TODAY...BUT WITH SOUTHWESTERLY FLOW DEVELOPING AND THE HIGH 
SHIFTING TO THE EAST THE LITTLE COLD SPOT UP IN THE NORTHWEST SHOULD 
NOT BE THERE.  MIXING DOWN 850 TEMPS FROM AVN WOULD GIVE A GENERAL 
MID TO UPPER 80S...SO WILL TRENDS TOWARDS THIS.  TONIGHTS LOWS WILL 
BE TEMPERED BY SOUTHWEST FLOW...AND MORE CLOUDS.  TRAJECTORIES AND 
DEWPOINT RISE WOULD INDICATE MID TO UPPER 60S. 

WEDNESDAY AND WEDNESDAY NIGHT...WITH THE SHIFTING OF THE DEVELOPING 
SURFACE LOW FURTHER NORTH...WILL BE KNOCKING BACK POPS...AND 
LIMITING TO THE SOUTH AND EAST. CANNOT ELIMINATE...NOT WITH UPPER 
LOW IN VICINITY...BUT WILL KEEP POPS LOWER WHERE MOISTURE AND 
SPECIFIC DYNAMICS LOOK LIMITED. TEMPS WARMER THAN GUIDANCE LOOK GOOD 
WITH STRONG SOUTHERLY FLOW IN WAA SOUTH OF DEVELOPING FRONT...AND 
MIXING DOWN OF 850 TEMPS WOULD INDICATE LOW 90S AS IN GOING 
PACKAGE.  WEDNESDAY NIGHT...WILL GO SLIGHTLY WARMER THAN GOING 
GUIDANCE...CLOSE TO GOING PACKAGE.

THURSDAY AND THURSDAY NIGHT...WITH THE SHIFTING OF THE PATTERN TO 
THE NORTH...IT APPEARS AS IF BEST PRECIP CHANCES WILL BE FARTHER 
NORTH THAN EARLIER ANTICIPATED.  WILL UP POPS A LITTLE IN THE NORTH 
DURING THE AFTERNOON...AND KEEP HIGH CHANCE POPS THERE DURING THE 
NIGHT.  FARTHER SOUTH...WILL LEAVE 20 POPS AFTERNOON...AND LOWER TO 
40 POPS FOR NIGHT.  

EXTENDED...FRI-MON UPPER LEVEL RIDGE BREAKS DOWN SOMEWHAT THROUGH 
PERIOD ALLOWING THIS PERIOD TO BE MORE ACTIVE WITH FASTER NW UPPER 
LEVEL FLOW.  SOME CONCERNS LINGERING OVER FROM THE SHORT TERM...WITH 
THE SURFACE LOW AND FRONT REMAINING NORTH.  FOR NOW WILL NOT MAKE 
ANY CHANGES...BUT LATER SHIFTS MAY NEED TO RAISE FRIDAY TEMPS...AND 
ADD MORE PRECIPITATION.

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

LRE