[LeArc] Forecast Discussion : MLI@ 5/4/2003 5:16:33 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 041010
AFDMLI

AREA FORECAST DISCUSSION...RETRANSMISSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
450 AM CDT SUN MAY 4 2003

LOOKS LIKE OCCASIONALLY ACTIVE 24-36 HR PERIOD ON TAP FOR THE CWA
WITH STRONG DYNAMICS AROUND DEVELOPING UPPER LOW. WILL BE SHORT TO BE
ABLE TO ASSIST WITH INCOMING WX WATCH. ETA AND GFS MORE SIMILAR NOW
IN SHEARING VORT LOBE OFF FIRST MAIN VORT CENTER TO AFFECT THE REGION
OVER THE CWA THROUGH MIDDAY/EARLY AFTERNOON. THIS MAIN VORT GETTING
CONVECTIVELY ENHANCED ATTM OVER NE. DEVELOPING LLVL JET AND VIGOROUS
WAA IN LOW TO MID LAYERS UNDER WAY JUST TO THE WEST...WITH REGIONAL
88D LOOP SHOWING ELEVATED THUNDERSTORM ACTIVITY HAS REALLY TAKEN OFF
FROM NE...INTO CENTRAL MO OVER THE PAST 1-2 HOURS. INCOMING VORT
LOBE...STRONGLY DIFFLUENT SOUTHWEST MID AND UPPER LEVEL FLOW AND
ASSOCIATED DIVERGENCE ALOFT...STRONG WAA IN THE LOW TO MID LEVELS...
ALL GENERATE STRONG BAND OF POS OMEGAS/LIFT THAT WILL SWEEP UP ACRS
THE CWA FROM SOUTHWEST-TO-NORTHEAST AS DAY PROGRESSES. INITIAL
ACTIVITY TRYING TO MAKE IT INTO THE SOUTHWEST CWA STRATIFYING OUT AS
IT GETS AWAY FROM BETTER ELEVATED SUPPORT FROM PROCESSES TO THE WEST.
BUT AGAIN...THESE PROCESSES(ESPECIALLY SOUTHERLY 50-60 KT H85 JET) TO
EVENTUALLY MAKE IT EAST INTO THE CWA BY MIDDAY AND JUICE UP AND
DESTABILIZE THE MID LAYER...FOR FIRST ROUND OF ELEVATED BUT ACTIVE
WEATHER. LARGE HAIL SHOULD BE THE MAIN INITIAL THREAT.

LIKE THE LATEST GFS AND UKMET SOLUTIONS OF A FURTHER SOUTH AND
SOMEWHAT SLOWER NORTHWARD SURGE OF WARM FRONT...TAKING INTO ACCOUNT
GRT LKS HIGH STILL HAVING ITS AFFECT. BUT FEEL EXTENT OF LLVL JET AND
DEEPENING SFC LOW SHIFTING UP INTO SOUTHWEST IA TO PULL THIS FRONTAL
FEATURE TO TOWARD THE SOUTHERN CWA BY THIS EVENING. MESOETA FCST
SOUNDING SHOWS A STORM REL HELICITY OF 666 M2/S2 AT BRL AROUND 00Z...
SUGGESTING THE SOUTHERN QUARTER TO 1/3 OF THE CWA TO BE IN FOR A
"DEVIL" OF A TIME THIS EVENING. QUICK LOOK AT BLEP TECHNIQUE AND
OTHER PARAMETERS SUGGEST THE SOUTHERN THIRD OF THE CWA AT RISK OF
SUPERCELLULAR STORMS IN VCNTY OF STRONGLY WRAPPING-UP WARM FRONT...
ALMOST AN OCCLUDED FRONT. EXTREME SHEAR AND LOW LCL'S/BOUNDARY LAYER
MOISTURE SUGGEST TORNADIC POTENTIAL FROM FAIRFIELD...TO MONMOUTH ON
SOUTH AT AROUND 00Z-02Z. FRONT MAY LOOK TO GET SHUNTED FURTHER TO THE
NORTH...BRINGING TROUBLE TO JUST SOUTH OF THE I-80 CORRIDOR BY
MIDNIGHT. NORTHERN THIRD OF THE CWA TO BE MAINLY UNDER HAIL THREAT
FROM LATE AFTERNOON AND ON INTO THE EVENING...BUT WOULD'NT RULE OUT
LATE NIGHT WINDS AS FRONT MAKES IT TO THE NORTHERN VCNTY LATE.

DRY SLOT WITH WARMER THERMAL SURGE WILL STILL TO LOOK TO SWEEP INTO
THE SOUTHERN 2/3'S OF THE CWA LATE TONIGHT AND MONDAY MORNING BEHIND
EXITING CONVECTIVE SYSTEMS FOR BRIEF WARM UP...POSSIBLY TO AROUND 80
DEGREES IN PORTIONS OF THE CWA BY MID AFTERNOON. FCST SOUNDINGS AND
LLVL LAPSE RATES SUGGEST VERY UNSTABLE CONDITIONS TO DEVELOP IN
VIEW OF LARGE SLOW MOVING UPPER LOW SYSTEM JUST TO THE NORTH...AND
SCTRD SHOWER AND THUNDERSTORM ACTIVITY MAY AGAIN DEVELOP BY
AFTERNOON. INCOMING VORT ROTATING AROUND UPPER SYSTEM TO ALSO HELP
SPAWN CONVECTIVE THREAT WITH SOME UPPER SUPPORT ON MONDAY.


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

$$

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