[LeArc] Forecast Discussion : MLI@ 8/16/02 2:14:13 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 161916
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
215 PM CDT FRI AUG 16 2002

.OVERVIEW...CONVECTION CONTINUES AT 18Z ALONG FRONTAL BOUNDARY TO SOUTH
OF AREA INTO MISSOURI RIVER VALLEY.  STRONG SYSTEM NOW DIVING INTO
MONTANA WITH SNOW REPORTED AT KCTB WITH 50+ KTS NW WINDS.  INTENSE
SUMMER LOW IN WESTERN SD MOVING EAST PUSHING WARM FRONT TOWARD AREA.
ALL MODEL QPF VERY POOR ON VERIFYING WARM FRONT CONVECTION WITH NGM
SIGNIFICANTLY BETTER THAN ETA/AVN.  BAROCLINIC RIBBON AND NOWCAST TOOLS
SUPPORT CONVECTION TO MOVE EAST THIS EVENING INTO FORECAST AREA ON
WARM FRONT AS STRONG UPSTREAM SYSTEM MOVES EAST.

...TIMING POPS AND TEMPS WITH FRONTAL PASSAGES TONIGHT AND SATURDAY AND
THEN POPS AGAIN MONDAY FORECAST CHALLENGE...

.DIAGNOSIS AND DAYS 1-3...AGAIN MODEL QPF ALMOST USELESS SIMILAR TO
LAST NIGHT EXCEPT FOR BASIC FORCING.  WATCH NEXT FEW HOURS AND PLAN FOR
SOME STORMS...NOW IN NW IOWA TO MOVE ALONG WARM FRONT THIS EVENING WITH
A FEW SEVERE WORDING DUE TO GOOD DYNAMICS AS STRONG LL JET CRASHES INTO
BOUNDARY AND MODERATE TO HIGH INSTABILITY. HIGHEST POPS NORTH OF I-80
AND SLIGHT CHANCE POPS OR NONE SOUTH SECTIONS. VERY WARM LOWS AND HUMID
TONIGHT ON SW WINDS OF 10-15 MPH LIMITING MIXING FOR LOWS 70 TO 75.
SATURDAY...FRONT DECELERATES SIMILAR TO PAST FEW SYSTEMS SO CONVECTION
TO WEST ALONG COLD FRONT TO GENERALLY DIMINISH AS MORNING PROGRESSES FOR
CHANCE POPS WITH FALLING TEMPS BY PM MOST AREAS BEHIND BOUNDARY. STRONG
WAA AHEAD OF BOUNDARY WILL GO ABOVE GUIDANCE FOR HIGHS...ESPECIALLY SW
2/3 OF AREA.  SOME SEVERE POTENTIAL TOMORROW BUT WILL PASS TO NIGHT
SHIFT AS DEPENDS ON WHAT HAPPENS TONIGHT WITH CONVECTION TO LARGE
EXTENT.  PERSISTENCE WITH PAST FEW COOLER AND DRIER AIRMASSES AND LIGHT
WINDS TOWARD MORNING SUPPORT GOING 1-2 CATEGORIES BELOW GUIDANCE FOR
LOWS SUNDAY AM...ESPECIALLY ALONG/NORTH OF I-80.  NICE DAY ON SUNDAY
WITH SFC HIGH OVERHEAD AND WILL GO NEAR MAV/FWC BLEND.  AVN/UKMET SHOWS
INCREASING CLOUDS SUNDAY NIGHT WITH PRECIPITATION SPREADING NORTH ON
MAINLY AS WARM FRONT APPROACHES. FORCING SUGGESTS HIGH POPS WARRANTED
MUCH OF AREA WITH IMPACTS ON HIGHS NORTH OF FRONT ON MONDAY...ALONG
AND SOUTH OF I-80.

.EXTENDED (TUE-FRI)...WARM FRONT PASSES TUESDAY WITH WARMER AND DRIER
CONDITIONS WEDNESDAY WITH NEXT FRONT ON THURSDAY WITH CHANCE POPS...SEE
MINOR MODEL TO MODEL VARIANCES OF MAIN MEDIUM MODELS BUT ALL ARE SIMILAR
ON MAIN PATTERN SO REASONABLE AND CONSISTENT WITH YESTERDAY MIX. WILL
TAKE HIGH SIDE OF MEX/FMR MID WEEK AHEAD OF NEXT BOUNDARY/FRONT WITH
GOOD WAA ON SOUTH TO SW WINDS AND SUNSHINE.

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

NICHOLS