[LeArc] Forecast Discussion : MLI@ 9/5/02 1:54:14 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 051859
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
155 PM CDT THU SEP 5 2002

.OVERVIEW...STALE LATE SUMMER PATTERN WITH BROAD UPPER RIDGE WELL
ENTRENCHED MOST OF CONUS WITH WEST COAST TROUGH ALLOWING FOR ABOVE
NORMAL TEMPS MOST OF CENTRAL 1/2 OF US.  SURFACE HIGH OVER GREAT LAKES
WITH WEAK RIDGE TRAILING BACK ACROSS NORTHEAST MISSOURI PRODUCING LIGHT
EAST TO SOUTHEAST WINDS AND CONTINUED LOW TO MODERATE HUMIDITY.
SATELLITE AND RADAR SHOWS SOME CLOUDS AND A FEW SHRA/TSRA AHEAD OF A
WEAK ELONGATED VORT MAX IN NORTHERN PLAINS INTO NORTHERN MIDWEST.
HIGHER DEWPOINTS STILL WELL WEST OF AREA TO SUGGEST ONLY SLOWLY HIGHER
DEWPOINTS NEXT 24 HOURS. LITTLE UPPER OR SURFACE FORCING TO SUGGEST ANY
CHANGES IN PATTERN IN ANALYSIS FIELDS.

...WARMUP NEXT FEW DAYS AND ANY POPS LATE TONIGHT AND FRIDAY NEAR TERM
ISSUES AND THEN MID WEEK COOL DOWN MEDIUM RANGE CHALLENGE...

.DIAGNOSIS AND DAYS 1-3...ETA LOW LEVEL THERMAL FIELDS REMAIN TOO COOL
AT NIGHT AND WARM IN DAY TO USE EXCEPT FOR TRENDS.  PERSISTENCE AND
TRAJECTORIES SUPPORT LOWS SLIGHTLY BELOW FWC/MAV GUIDANCE WITH STILL
DECENT RADIATIONAL COOLING.  HIGHS TO APPROACH NEAR BLEND OF GUIDANCE.
WEAK VORT MAX BASED ON SATELLITE AND RADARS SUPPORT SLIGHT CHANCE POPS
LATE TONIGHT NORTHWEST 1/3 AND 1/2 TOMORROW BUT ANY PRECIPITATION TO BE
IN DECAYING STAGES OVERALL AND THUS SPOTTY AND LIGHT.  DIFFUSE WARM
FRONT PASSES SATURDAY FOR WARMER AND HUMID CONDITIONS INTO SUNDAY BUT
NO TRIGGER EVIDENT FOR POPS.  PATCHY FOG MAY ONCE AGAIN FORM TONIGHT
WITH LIGHT WINDS BUT LOW DEWPOINTS SUGGEST NOT WIDESPREAD ENOUGH TO
INCLUDE IN ZONES AS ANTICIPATE SIMILAR TO LAST NIGHT OVERALL.

.EXTENDED (MON-THU)...MOTHER NATURE ON SCHEDULE WITH SLOW MOVING BUT
SIGNIFICANT FRONT TO PASS WEDNESDAY BASED ON ALL MEDIUM MODELS.
SINCE SUN IS MOVING SOUTH AT ~25 NM PER DAY...MODEL TENDENCY FOR COOL
AIR TO REMAIN OR BECOME EVEN COOLER (STRONGER) AS FRONT APPROACHES IS
REASONABLE. UKMET/AVNXT SUGGEST WEAK WAVE TO PASS WITH FRONT FROM
SHORT WAVE OUT OF CURRENT WEST COAST TROUGH SO PRECIPITATION WITH FROPA
FAIRLY CERTAIN...ESPECIALLY WITH STRENGTH...BUT WILL KEEP CHANCE POPS
FOR NOW DUE TO POTENTIAL TIMING ISSUES.  TEMPS...TREND NEAR TO ABOVE MEX
TIL FROPA AND THEN BELOW BY 1-2 CATEGORIES WED/THU WITH DEFINITELY
COOLER AIR.  ONLY FLY IN OINTMENT IS POTENTIAL TROPICAL DEVELOPMENT IN
GULF THAT COULD INCREASE SIGNIFICANTLY AMOUNTS WITH/AHEAD OF FROPA...
SHOULD KNOW CHANCES OF THIS HAPPENING NEXT 36 TO 48 HOURS.

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

NICHOLS