[LeArc] Forecast Discussion : MLI@ 10/17/02 1:57:41 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 171904
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
200 PM CDT THU OCT 17 2002

.OVERVIEW...MIDWEST UNDER VIGOROUS NORTHWEST FLOW WITH EMBEDDED SHORT
WAVES.  JET AXIS SOUTH OF AREA ALLOWING FOR FAVORABLE LOW CLOUDS AND
LIGHT PRECIPITATION SITUATION WITH SHORT WAVES.  UPPER AIR ANALYSIS
SUPPORTS WEAK TO MODERATE RISING HEIGHTS AND THUS SOME RIDGING INTO AREA
TONIGHT FOR SOME PARTIAL CLEARING AHEAD OF ANOTHER ALBERTA CLIPPER
SYSTEM.  TIMING OF PARTIAL CLEARING TO REACH NW 1/3 AREA BY SUNSET AND
THEN SPREADING OVER REST OF AREA TONIGHT.   RADAR SUGGESTS SOME LIGHT
SPRINKLES AND RAIN MAY CONTINUE IN ILLINOIS NORTH OF HIGHWAY 34 EARLY
THIS EVENING BEFORE CLEARING MOVES IN.

...CLEARING AND WARMUP TOMORROW AND THEN NEXT COOL-DOWN FORECAST ISSUES
THIS CYCLE...

.DIAGNOSIS AND DAYS 1-3...MODELS VERIFY ADEQUATELY ON LOW CLOUDS WITH
ETA BEST AND WILL USE ETA DYNAMICS MAINLY WITH SOME INPUTS FROM
AVN/UKMET FOR BL TEMPS. THUS...PARTIAL CLEARING MOST AREAS...MAINLY SW
1/2 TO 2/3 TONIGHT WITH MAYBE SOME EARLY EVENING SPRINKLES IN ILLINOIS
WHICH WILL USE NOWCAST TOOLS TO DECIDE IF NEEDED.  SOME MID CLOUDS ALSO
TONIGHT WITH NEXT SHORT WAVE. WITH SOME CLOUDS AND SOUTH WINDS WILL GO
ON HIGH SIDE OF GUIDANCE BLEND FOR LOWS MOST AREAS.  WARM FRONT TO PUSH
NORTH TONIGHT AND LITTLE FORCING PER LATEST ANALYSIS SO NO POPS TONIGHT
BUT NEXT BATCH OF RAIN SHOULD BE NORTH OF HIGHWAY 20 BY DAWN FRIDAY.
FRIDAY...GOOD WARMUP WITH SW TO WEST WINDS SO GO 1-2 CATEGORIES ABOVE...
ESPECIALLY SW 1/2 AREA UNDER PARTLY TO MOSTLY SUNNY SKIES.  THEN NEXT
COOL DOWN WITH SOME LOW CLOUDS LATE NIGHT NORTH OF HIGHWAY 30 LATE BUT
OTHERWISE LITTLE FORCING FOR PRECIPITATION...QUIET INTO SATURDAY NIGHT
WITH TEMPS NOT TOO FAR FROM GUIDANCE BLEND WHICH ARE ALL FAIRLY CLOSE
AND SEE NO REASON FOR MAJOR DEVIATIONS.  FOR SUNDAY...LARGE SCALE
FORCING OF RETROGRADING SHORT WAVE SUPPORTS CHANCE OF SLIGHT OVERRUNNING
IN IOWA TOWARD LATE SUNDAY WITH NEXT SHOT OF EVEN COOLER AIR AS LONG
WAVE TROUGH SHOWS LITTLE INDICATIONS OF MOVING. WILL JUST MENTION RAIN
FOR NOW BUT CHANCE OF SNOW CAN/T BE RULED OUT AS CONSERVATIVE
INDICATIONS SUGGEST LL TEMPS TO BE A FEW DEGREE COOLER MOST LOCATIONS BY
MONDAY AM.

.LONGER RANGE(MON-THU)...12Z UKMET SUPPORTS LATEST AVN AND TO CERTAIN
EXTENT...ECMWF OF SLIGHT OVERRUNNING WITH EVEN STRONGER COLDER PUSH
MONDAY INTO MONDAY NIGHT SOUTHERN 2/3 AREA.  WILL INCLUDE CHANCE OF
RAIN AND SNOW AND VERY COOL TEMPS NEAR MEX/FMR BLEND.  HARD FREEZE VERY
PROBABLE MID WEEK AS STRONG CANADIAN HIGH BUILDS IN.

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

NICHOLS