[LeArc] Forecast Discussion : MLI@ 7/13/2003 4:37:22 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 130934
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
425 AM CDT SUN JUL 13 2003

PERSISTENT LOWER LEVEL AC SEEN ON IR FOG(11U-3.9U)LOOP FROM WEST OF
DBQ...THROUGH THE QUAD CITIES...AND TO EAST OF GALESBURG...PROBABLY
BEING MAINTAINED ON LEE SIDE OF VORT GRADIENT OF WEAK UPPER WAVE
SHIFTING SOUTH THRU CENTRAL IA ATTM. A FEW ISOLATED SHOWERS HAVE
EVEN MAINTAINED OVERNIGHT FROM EAST OF MLI...TO NOW SKIRTING THE
EASTERN DVN/NORTHERN ILX CWA BOUNDARY. WILL NOT MENTION THESE IN
ZONES AS FEEL THEY WILL DECAY...OR EXIT THE CWA THIS MORNING.

OTHERWISE...SIMILAR DAY ON TAP TODAY AS SATURDAY...MAYBE A DEGREE OR
TWO WARMER...ALTHOUGH LIGHT FLOW IN LOWER LEVELS/RIDGE AXIS TO
LIMIT MIXING. THUS TEMPERATURES RISING ABOVE CONVECTIVE LEVELS...
LINGERING CYCLONIC FLOW ALOFT...STEEP LAPSE RATES IN LOWER TO MID
LEVELS WITH ADEQUATE RH'S AGAIN TO PRODUCE AFTERNOON CU. WOULDN'T
RULE OUT AN ISOLATED LATE AFTERNOON/EVENING SHOWER AGAIN...ALTHOUGH
FCST SOUNDINGS SUGGEST WARM WEDGE DEVELOPING ABOVE H7 MB THIS EVENING
MAYBE TO PUT LID ON POTENTIAL. THUS FEEL PRECIP THREAT TOO LIMITED TO
MENTION AT THIS TIME.

SOUTH TO SOUTHWEST H85 FLOW TO INCREASE LATE TONIGHT...AND
ESPECIALLY MONDAY ON BACKSIDE OF EASTWARD RETREATING LLVL
ANTICYCLONE. THIS FETCH TO EVENTUALLY TAP INTO PORTION OF WARM H85
THERMAL POOL TO THE WEST...AND PUMP UP H85 TEMPS AT LEAST INTO THE
UPPER TEENS CELSIUS BY 00Z TUE. SOUTHERLY SFC GRADIENT MAY TIGHTEN
ENOUGH FOR 10 TO 20 MPH SOUTHERLY WINDS ON MONDAY...ESPECIALLY ACRS
THE WEST HALF OF THE CWA. THIS FACTOR AND ASSOCIATED MIXING IN
MODERATING AIRMASS SUGGESTS MID TO UPPER 80S TO BE EASILY
OBTAINED OVER MUCH OF THE CWA FOR MONDAY HIGHS...WITH SOME 90S
POSSIBLE.

INTERESTING WX SCENARIO UNFOLDING FOR MONDAY NIGHT AS TROUGH DIGS
INTO UPPER MIDWEST...WITH PROGRESSIVE COLD FRONT AT THE SFC.
BUILDING INSTABILITIES OUT OF AHEAD OF FROPA(MODELS SUGGEST 3K J/KG
CAPES AND LI'S OF -7...PLUS STEEPENING MID LEVEL LAPSE RATES
BUILDING THRU 06Z TUE)...AS WELL AS 30-35 KT SOUTHWESTERLY H85 JET
MAXIMIZING THTA-E ADVECTION INTO INCOMING BOUNDARY...SUGGESTS PLENTY
OF FUEL TO FEED LIKELY INCOMING LINEAR MCS. ETA INDICATES DIFFLUENT
NOSE OF INCOMING 120+ KT JET MAX DIGGING INTO TROUGH BASE ALSO TO
PRODUCE IMPRESSIVE DIVERGENT BULLSEYE RIGHT OVER THE LOCAL AREA BY
MIDNIGHT. AS IT LOOKS NOW...INGREDIENTS THERE TO SUPPORT A LIKELY
CONVECTIVE EVENT MONDAY NIGHT FOR AT LEAST NORTHWEST HALF OF THE CWA.

ALL IN ALL...MADE LITTLE CHANGES TO ONGOING PACKAGE AS STILL LOOKS
TO BE ON TARGET.


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

$$

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