[LeArc] Forecast Discussion : MLI@ 10/3/02 1:59:25 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 030706
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
205 AM CDT THU OCT 3 2002

.OVERVIEW...BIGGEST FEATURES AT 06Z IS HURRICANE LILI APPROACHING
LOUISIANA COAST AND BROAD WEST COAST UPPER LOW NOW IN AZ MOVING EAST.
PLAINS FRONTAL SYSTEM HAS NOW NEARLY STALLED AT 06Z AND EXTENDS FROM
CENTRAL INDIANA TO SE KANSAS AND BACK INTO SOUTHERN TX PANHANDLE.
MODERATE AMOUNT OF PRECIPITATION DEVELOPING PAST FEW HOURS ALONG
BOUNDARY FROM NEAR STL TO NEAR DDC.  SFC AND SATELLITE SHOWS COPIOUS
CLOUDS IN CENTRAL US DUE TO SW FLOW CAUSING OVERRUNNING OF COOL AIR.

...RAIN RETURNING TODAY AND THEN SHOWERS AND STORMS LATE TONIGHT AND
FRIDAY WITH VIGOROUS UPPER LOW AND ADDED MOISTURE FROM LILI AN ADDED
CONCERN FOR HEAVY RAINS...

.DIAGNOSIS AND DAYS 1-3...MODELS INITIALIZE AND VERIFY WELL WITH ETA
QPF BETTER THAN HAS BEEN THE CASE FOR SEVERAL RUNS.  WILL COUPLE MODEL
FORCING WITH GENERAL QPF AND CONCEPTUAL FRAMEWORK...THIS SUPPORTS AREA
OF RAIN MOVING BACK INTO CENTRAL AND SOUTH SECTIONS BY MID DAY WITH
EMBEDDED THUNDER SOUTH WITH WEAK TO MODERATE OVERRUNNING AS WARM FRONT
APPROACHES.  RAIN TO REACH FAR NORTH SECTIONS MID TO LATE PM WITH MOST
AREAS RECEIVING AROUND A QUARTER INCH TO POSSIBLY AS MUCH AS HALF INCH
AMOUNTS.  TEMPS TO RISE TONIGHT AFTER WARM FRONT PASSES AS STRONG WAA
AND BREEZY SOUTH WINDS RESULT IN TEMPS IN UPPER 60S TO LOWER 70S BY
MORNING. SIGNIFICANT AMOUNT OF MOISTURE FROM LILI TO PROVIDE SHOWERS AND
SOME STORMS POSSIBLE THOUGH MAY BE TOO MOIST FOR STORMS. FRIDAY...A
CONCERN FOR FLOODING THREAT AND EVEN CAN/T RULE OUT SEVERE POTENTIAL.
MODERATE TO HEAVY RAINS A NEAR CERTAINTY WITH STRONG FORCING...HIGH
MOISTURE IN PLACE TO RESULT IN SOME FLOODING DUE TO NOW WET GROUNDS...
ESPECIALLY CENTRAL AND NORTH SECTIONS.  MARGINAL INSTABILITY BUT CAN/T
RULE OUT SOME STRONG TO SEVERE STORMS WITH INTENSE LOW LEVEL JET OF 50-
65 KTS AT 850MB IF GET ENOUGH HEATING FOR SOME DAMAGING WINDS FROM
MOMENTUM TRANSFER WITH INTENSE LINE OF SHOWERS AND STORMS (I.E. SQUALL
LINE THAT MAY WITH ENOUGH HEAT PRODUCE SOME BOWING SEGMENTS). WILL
EMPHASIZE IN HWO AND NOT MENTION IN ZONES BUT NEXT COUPLE OF SHIFTS NEED
TO WATCH FOR THIS POTENTIAL. ALSO...LOTS OF 0-1 KM SHEAR SUPPORTS
ROTATION AS FRONT PASSES...ALL DEPENDS ON TEMPS AND ANY HEATING!   HIGH
TEMPS TO OCCUR EARLY TO MID DAY WITH FALLING TEMPS BY PM AS COLD AIR
CRASHES IN.  KEEP SOME CLOUDS IN WITH UPPER TROUGH FRIDAY NIGHT TO LIMIT
TEMPS COOLING SOMEWHAT.  OVERALL WENT WITHIN 1 CATEGORY OF TEMPS TODAY
AND ON HIGH SIDE TONIGHT AND FRIDAY...THEN NEAR MIX FOR PERIODS 3 AND 4.
RISK OF FLOODING WILL CONTINUE ESF AND HIT HARD FRIDAY TIMING WITH
FRONTAL PASSAGE OF WIDESPREAD .75 TO 1.5 INCH PLUS AMOUNTS WITH SOME
LOCALLY HIGHER AMOUNTS.

.EXTENDED...(SUN-WED)...NW FLOW CLIPPER SYSTEM PASSES ON SUNDAY WITH AVN
STRONGEST AND FAIRLY WET.  ECMWF AND UKMET NOT AS INTENSE WITH TRIGGER
SO PLAN TO LEAVE AS CHANCE POPS.  STRONGER SHOT OF COLD AIR MONDAY INTO
TUESDAY WITH KILLING FROST & FREEZE PROBABLE MOST LOCATIONS NEXT WEEK.

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

NICHOLS