[LeArc] Forecast Discussion : MLI@ 8/10/2003 4:32:59 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 100930
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
415 AM CDT SUN AUG 10 2003

AMPLIFYING UPPER RIDGE OVER THE ROCKIES EFFECTIVELY REINFORCES
STEEP NORTHERLY FLOW DOWN ACRS THE AREA TODAY AND INTO MONDAY.
RATHER SIGNIFICANT VORT SEEN ON W/V IMAGERY OVER NORTHWEST MN...
WILL LOOK TO GET DUMPED DOWN ACRS IA THIS AFTERNOON IN THIS FLOW.
PROBLEM IS WITH WEAK RIDGE OF HIGH PRESSURE AND ALMOST WASHED-
OUT COOL FRONT ALREADY PUSHING INTO THE AREA...FEATURE WILL BE
PROPAGATING ACRS A WEAKLY SHEARED AND MARGINALLY UNSTABLE AIRMASS.
SHORT RANGE MODELS INDICATE MUCH BETTER CONVECTIVE SUPPORT TO DEVELOP
OUT TO THE WEST ACRS SD...NE...AND WESTERN IA THIS AFTERNOON AND
OVERNIGHT. MSAS AND LATEST SFC ANALYSIS SHOWING LARGE PRESSURE FALLS
OVER SD INTO NE ATTM...AND SETTING UP TO BE AN ACTIVE DAY ACRS THESE
AREAS.  BUT WITH A VORT OF THIS MAGNITUDE AND INCOMING CVA
GRADIENT SO CLOSE TO THE LOCAL CWA...WILL HAVE TO KEEP 20-30 POPS
GOING FROM AFTERNOON ON...ESPECIALLY ACRS THE WEST...FOR THE
POTENTIAL OF UPSTREAM CONVECTION POSSIBLY BLEEDING INTO THE AREA.
MODEL TEMPERATURE GUIDANCE SEEMS WARM...TAKING INTO ACCOUNT THAT THE
CWA SHOULD BE UNDER THE INFLUENCE OF SOME MID TO HI LEVEL CLOUD
DEBRIS FILTERING INSOLATION AT TIMES TODAY...AND WITH WEAK LLVL WIND
REGIME MEANING MINIMAL MIXING. WILL TREND TOWARD LOW TO MID 80S.

JET ENERGY FUNNELING DOWN LEE SIDE OF SHARPENING UPPER RIDGE AND
INTO THE SOUTHERN PLAINS...MAKES FOR SOME RETROGRADE OF EASTERN
CONUS TROUGH TOWARD THE LOWER MS RVR VALLEY ON MONDAY. SHORT RANGE
MODELS SUGGEST INCOMING VORT TO GET CAUGHT UP IN RESULTANT SQUEEZE
PLAY BETWEEN UPPER RIDGE AND TROUGH...AND SLOW ACRS THE IA/NORTHWEST
MO BORDER THROUGH 18Z MON. WEAK...TO WASHED OUT FRONTAL BOUNDARY
WILL WAVER OVER THE SOUTHERN CWA ON MONDAY...AND MODELS SUGGEST SOME
DEVELOPING 1000-H85 THTA-E CONVERGENCE ACRS THAT SAME AREA FROM THE
NORTHEAST AS LARGE LLVL HIGH PUSHES ACRS THE NORTHERN GRT LKS. THUS
WOULD FEEL BEST CHANCE OF MONDAY PRECIP WOULD BE ACRS THE SOUTHERN
HALF TO THIRD...BUT MOST OF THE VARIOUS SHORT RANGE MODEL QPF'S
SUGGEST THE ENTIRE CWA TO BE AT RISK. HAVE RELUCTANTLY BLANKETED THE
ENTIRE CWA WITH 30 POPS WITH UNCERTAINTIES. COOLING THICKNESSES FROM
THE NORTHEAST OFF CENTER OF LLVL ANTICYCLONE SUGGEST HIGHS AROUND
80/LOWER 80S ON MONDAY. SFC RIDGE AXIS TO CONTINUE TO PUSH ACRS THE
AREA FROM THE NORTH FOR CLEAR OUT MONDAY NIGHT...AND TUESDAY
MORNING LOWS DIPPING INTO THE 50S ACRS THE NORTH.

NO CHANGES TO LONGER RANGE FOR NOW...


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

$$

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