[LeArc] Forecast Discussion : MLI@ 3/15/03 5:00:39 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 151108
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
500 AM CST SAT MAR 15 2003

IR FOG LOOP INDICATING ANOTHER ROUND OF LLVL STRATUS QUICKLY
ADVECTING NORTH ACRS THE LOCAL CWA...SURGING AROUND WESTERN RIDGE
AXIS. SFC OBS INDICATE WIDESPREAD DENSE FOG AND EVEN SOME PATCHY
DRIZZLE IN THIS "GRUNGE" DECK...AND HAVE JOINED ADJACENT OFFICES
WITH A DENSE FOG ADVISORY UNTIL 10 AM THIS MORNING. HAVE
EXTRAPOLATED WHERE DECK WILL SEEP ACRS AND NEAR THROUGH 8 AM(WHICH
INCLUDES MOST OF THE CWA EXCEPT THE 4 NORTHWEST CORNER COUNTIES) FOR
ADVISORY OUTLINE. FCST SOUNDINGS SUGGEST WARM WEDGE ALOFT/INVERSION
WILL TRAP STRATUS FOR AWHILE...BUT EXPECT BETTER MIXING REGIME THAN
YESTERDAY TO DEVELOP BY LATE MORNING TO HELP EROSION PROCESS. 06Z
META PROGGED BOUNDARY LAYER RH HANDLING THIS DECK REASONABLY WELL...
AND SUGGESTS NORTHWEST IL LAST TO MIX OUT DURING THE EARLY AFTERNOON.
FAR EAST CENTRAL CWA/I-80 CORRIDOR EAST OF MS RVR MAY ALSO FINALLY
ERODE AT THIS LATER TIME. MUCH LIKE YESTERDAY...THESE LOW CLOUDS
AND LINGERING MOISTURE TO ACT AS THE "FLY" IN WARM UP POTENTIAL
OINTMENT...ESPECIALLY ALONG AND EAST OF THE MS RIVER. HAVE TRENDED
DOWN HIGHS FROM PREVIOUS PACKAGE AND TO LEVELS OF COOLEST GUIDANCE.
THAT MAY EVEN BE TOO WARM. DELAYED BOUGHT OF INSOLATION...INVERSION
ON WEST SIDE OF SFC RIDGE PREVENTING DECENT MIXING WINDS...AND
LINGERING HAZE/AMBIENT MOISTURE DEBRIS AFTER STRATUS EROSION
ACTING AS THERMAL SPONGE...REALLY DAMPENED THURSDAY WARM UP OVER THE
DVN CWA.

NEG TILTED WAVE NOW OVER THE WESTERN INTER-MOUNTAIN REGION...WILL
PROPAGATE EASTWARD AND BATTLE ITS WAY INTO RIDGE CREST LATE TONIGHT
AND SUNDAY. MAIN VORT PIECE ASSOCIATED WITH UPPER WAVE TO PUSH ALONG
MN/IA BORDER SUNDAY MORNING...WITH CVA OUT AHEAD OF IT BUILDING ACRS
THE CWA SUNDAY AFTERNOON. AS NORTHERN PLAINS FRONT SAGS TOWARD THE
NORTHERN CWA LATER SUNDAY...MAY BE FOCUS FOR SOME SHOWER AND
THUNDERSTORM ACTIVITY. ETA SUGGESTING CAPES TO THE SOUTHEAST OF
THIS FEATURE BUILDING OVER A 1000 J/KG BY 00Z MON MAY BE OVERDONE
DEPENDING ON EXTENT OF ACTUAL WARMING AND SFC DPTS COMBINED WITH
ADEQUATE FORCING...BUT STILL APPEARS MAY BE ENOUGH FOR STORM
DEVELOPMENT BY LATE SUNDAY AFTERNOON...ESPECIALLY SUNDAY NIGHT.

STRONGER SOUTHERLY SFC FLOW AND MIXING POTENTIAL TO FINALLY REALIZE
WARMING POTENTIAL FROM ALOFT ON SUNDAY...ESPECIALLY IF MORE SUNSHINE
THAN CLOUDS CAN OCCUR. WELL ADVERTISED WEEKEND 70S MAY FINALLY
HAPPEN...WITH SHORT RANGE MODEL THERMAL PROFILES SUGGESTING MID 70S
MAY EVEN BE POSSIBLE ACRS THE WESTERN AND SOUTHERN CWA IF ENOUGH
MIXING AND INSOLATION OCCUR. BUT EXPECT MORE CLOUDS THAN SUN AND WENT
MORE CONSERVATIVE AROUND 70 TO LOWER 70S FOR NOW.

NO CHANGES TO LONGER RANGE.

COORDINATED WITH ILX...THANX!

.DVN...
IA...DENSE FOG ADVISORY TIL 16Z/10 AM FOR EAST CENTRAL AND SOUTHEAST
IA.
IL...DENSE FOG ADVISORY TIL 16Z/10 AM FOR NORTHWEST AND WEST CENTRAL
IL.
MO...DENSE FOG ADVISORY TIL 16Z/10 AM FOR FAR NORTHEAST MISSOURI.

$$

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