[LeArc] Forecast Discussion : MLI@ 9/13/02 3:17:44 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 130824
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
320 AM CDT FRI SEP 13 2002

TODAY SHOULD BE CHARACTERIZED BY FILTERED SUNSHINE THROUGH MID TO
UPPER LEVEL DEBRIS FROM THE WEST...OFF PLAINS VORT AND INTERMINGLING
H85 SOUTHERLY INFLUX PRECIPITATION PROCESS.  SOME OF THIS ELEVATED
PRECIPITATION SHOULD MAKE IT ACRS CENTRAL IA THIS AFTERNOON...BUT
WILL BANK ON DRIER SOUTH-SOUTHEAST SFC-H85 FLOW TO KEEP IT FROM
CREEPING ACRS THE WESTERN CWA BORDER. SOUTHWEST MID TO UPPER LEVEL
FLOW SHOULD LEAD TO MORE SATURATION IN THOSE LAYERS HOWEVER. THUS...
WOULD THINK ONGOING PARTLY CLOUDY SHOULD COVER FLAVOR OF DAY...BUT BY
LATE AFTERNOON MUCH OF CWA PROBABLY WILL BE IN MORE OF A MOSTLY
CLOUDY STATE. EVEN WITH MID TO HIGH LEVEL CLOUD AND MOISTURE
INCREASE...THERMAL PARAMETERS AND ENOUGH FILTERED INSOLATION SUGGEST
AT LEAST UPPER 70S TO BE REACHED ACRS MOST OF THE CWA.

NORTHERN BRITISH COLUMBIA WAVE...SEEN ON THIS EVENINGS 00Z UA
ANALYSIS AND CURRENT W/V IMAGERY...IS SIMILARLY PROGGED BY SHORT
RANGE MODELS TO DROP SOUTHEAST TOWARD THE NORTHERN GRT LKS THROUGH
SAT MORNING. AS IT DOES...MID ROCKIES/WESTERN HIGH PLAINS VORT WILL
BE DRAWN TOWARD THIS TRANSITION IN HOPEFUL PHASING PROCESS. APPEARS
BETTER VORT DYNAMICS WILL SHEAR BOTH NORTH AND SOUTH OF THE CWA SAT
AFTERNOON AND EVENING AS TROUGH DIGS ACRS THE WESTERN GRT LKS. LATEST
UKMET AND AVN SATURATE COLUMN ENOUGH TO ALLOW LIGHTER OVER-RUNNING
RAINS TO BLEED ACRS THE NORTHEAST CWA BY LATE FRI NIGHT...WHILE
ETA/META KEEP PRECIP JUST TO THE WEST THROUGH 12Z SAT. LOOKING AT
ISENTROPIC LIFT AND SATURATION BY LATE TONIGHT AND SIMILAR PROCESSES
GOING ON ATTM ACRS FAR WESTERN IA/EASTERN NE...WILL KEEP AT LEAST 30
POPS FOR LATE TONIGHT ACRS THE WEST. FORECAST SOUNDINGS SHOW ELEVATED
INSTABILITY PARAMETERS IN SUPPORT OF THUNDER BY LATE FRI NIGHT...BUT
WITH THE EXTENT OF LOWER TO MID LEVEL MOISTURE RETURN STILL AT
QUESTION...WILL KEEP RAIN WORDING FOR NOW. MAY BE NOT MUCH MORE THAN
SPRINKLES THROUGH 12Z. TIMING DIFFERENCES STILL THERE ON EVENTUAL
FROPA ON SAT. AVN AND UKMET BECOME MORE PROGRESSIVE THAN THE ETA...
WHICH DEVELOPS RETARDING CLOSED SFC WAVE ACRS EASTERN IA AND NORTHERN
IL SAT AFTERNOON. 00Z ETA EVEN MAINTAINS WAVE INTO EAST
CENTRAL/SOUTHEAST IL INTO SAT NIGHT...WITH OVER-RUNNING PRECIP
CONTINUING ACRS EASTERN CWA INTO SUN MORNING. WILL LEAN TOWARD
AVN/UKMET CONSENSUS OF BLOWING OUT PRECIP OF EASTERN CWA BY LATE SAT
NIGHT...AS INCOMING SFC HIGH SUBSIDENCE AND ISENTROPIC LIFT SHUT-OFF
IS REALIZED. ALTHOUGH A REAL GOOD MOISTURE TRANSPORT SET-UP DOES NOT
LOOK TO MATERIALIZE INTO THE FRONTAL SYSTEM ON SAT...WILL BUMP UP
POPS TO LIKELY STATUS ACRS THE NORTH...WITH BULK OF ACTIVITY TO OCCUR
DURING THE AFTERNOON INTO EARLY EVENING PERIODS. FEEL ONGOING HIGHS
FOR SAT A BIT WARM AND WILL TONE DOWN...TAKING INTO ACCOUNT A MORE
SATURATED VERTICAL COLUMN HAMPERING THERMAL WARM UP POTENTIAL.

NO CHANGES TO LONGER RANGE PERIODS.


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

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