[LeArc] Forecast Discussion : MLI@ 3/16/03 4:58:00 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 161105
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
459 AM CST SUN MAR 16 2003

NO REAL ADVECTIVE STRATUS/FOG DECK PUSHING ACRS OR TOWARD THE CWA
THIS MORNING LIKE THE PREVIOUS TWO DAYS...THUS SHOULD BE AN
EARLIER ROUND OF INSOLATION WITH NO DECK TO ERODE. CURRENT
TEMPERATURES OVER THE CWA RANGING WIDELY FROM 29...TO 47 DEPENDING
ON LOCALIZED WIND STRENGTH AND DIRECTION. BUT TEMPERATURES
THIS MORNING ARE GENERALLY WARMER THAN THE PREVIOUS TWO DAYS IN
MOST LOCATIONS...AND WITH WARMER START AND NO GRUNGE DECK TO ERODE...
YESTERDAYS PREDICTED HIGHS MAY BE FINALLY REALIZED TODAY. SOUTH
WINDS AT OR SOMEWHAT ABOVE YESTERDAYS VALUES...SHOULD HELP MIXING
FACTOR AS WELL FOR WARMER HIGH POTENTIAL. OF COURSE...STILL WET AND
COOL GROUND COMBINED WITH MID AND HIGH LEVEL DEBRIS CLOUDS FROM THE
WEST...WILL COUNTERACT WARM UP POTENTIAL. THUS CAME UP WITH HIGH
TEMPS NEAR TO WHAT'S ALREADY ADVERTISED BY PREVIOUS PACKAGE(GENERALLY
MID TO UPPER 60S)...ALTHOUGH HOPED FOR 70 DEGREE READINGS MAY
FINALLY TICKLE WESTERN AND SOUTHERN EDGES OF THE CWA. BUT
OPTIMISTIC THINKING ALSO TEMPERED BY THE FACT THAT THE SOUTH TO
SOUTHEAST SFC FETCH STILL TO TAP INTO LINGERING RIDGE AXIS AIRMASS
NEAR THE MO BOOT HEEL...WHICH IS NOT THE REAL WARM AIR LIKE JUST TO
THE WEST...THUS AGAIN SUPPORTS PLAYING COOLER SIDE OF THINGS FOR
TODAYS HIGHS. PATCHY AREAS OF DENSE FOG MAINLY ACRS THE FAR EASTERN
AND NORTHEAST CWA SHOULD MIX OUT BY MID MORNING...BUT WILL ADD
MORNING FOG MENTION IN MOST ZONE GROUPS.

CWA TO LIE MAINLY IN BETWEEN VARIOUS VORT PROPAGATION PATHS TODAY...
WITH MAIN VORT SHEARING ACRS SOUTHERN AND CENTRAL MN...AND SOUTHERN
PLAINS VORT COMPLEX PUSHING NORTHEAST INTO WESTERN MO BY LATE IN THE
DAY. THUS FEEL CWA NOT TO BE UNDER A PRECIP THREAT FOR THE FIRST
PERIOD. BUT AS NORTHERN PLAINS FRONT SAGS TOWARD THE NORTHERN CWA
TONIGHT...AND MO VORT AND TRAILING LOBE OFF MN/WI VORT APPROACHES...
MAY BE ENOUGH FORCING FOR SHOWER THREAT MAINLY ACRS THE NORTH. IF
ANYTHING...MAYBE SHOWER ACTIVITY GENERATED CLOSER TO MAIN FORCING
OVER WI AND SOUTHEAST MN MAY BLEED SOUTH INTO THE CWA LATE. SOME
MID LEVEL INSTABILITY DEVELOPING OVERNIGHT AS WELL THAT MAY HELP
SHOWER CHANCE. WITH INCREASING DPTS TODAY AND TONIGHT INTO UPPER 40S
AND LOWER 50S OVER COOL GROUND...MAY BE ANOTHER LLVL STRATUS AND FOG
SCENARIO BREAKING OUT OR ADVECTING ACRS THE CWA TONIGHT.

ON MONDAY...SQUEEZE PLAY STARTS TO DEVELOP OVER THE LOCAL AREA...AS
CANADIAN HIGH DROPS ACRS THE NORTHERN GRT LKS...AND LARGE CUT OFF
UPPER LOW ROLLS ACRS THE SOUTHERN PLAINS. SFC WINDS SHOULD BACK TO
THE EAST-SOUTHEAST BY LATE MONDAY...WITH BEST SFC CONVERGENCE AND
FORCING NEAR FRONT GETTING SQUEEZED JUST NORTH OF THE CWA. THUS FEEL
BEST SHOWER AND POSSIBLE THUNDERSTORM CHANCE ON MONDAY TO CONTINUE
ACRS THE FAR NORTH...WITH REST OF THE CWA POSSIBLY REMAINING DRY.
BUT CONCERN WITH LINGERING ABOVE MENTIONED VORT FRESH OUT OF MO THAT
MAY KICK UP A FEW SHOWERS FURTHER SOUTH AND HAVE KEPT MONDAY
CHANCE...ALTHOUGH LOWERED POPS. SOUTHEAST FLOW SLOSHING COOLER AIR
BACK FROM RIDGE TO THE EAST...COMBINED WITH CLOUD COVER AND LINGERING
STRATUS AND FOG TO LIMIT MONDAY HIGHS. NORTHEAST CWA MAY NOT GET OUT
OF THE 50S.

WITH STRENGTH OF GRT LKS HIGH AND NEG TILT OF SOUTHERN PLAINS CUT OFF
CYCLONE SYSTEM RETARDING ITS FORWARD PROPAGATION...MODELS ARE SLOWER
IN WHIRLING MAIN PRECIP BANDS TOWARD THE CWA. MONDAY NIGHT ONCE
LOOKED PROMISING...NOW MAY BE ALMOST DRY. INCREASING LLVL DRIER
EASTERLY FLOW WILL ALSO HURT PRECIP CHANCES AND HAVE LOWERED MONDAY
NIGHT POPS OF OVERRUNNING RAIN. DAY SHIFT WILL HAVE TO ASSES
FURTHER DOWNPLAY OF PRECIP THREAT MONDAY NIGHT...AND EVEN INTO
TUESDAY. WENT WITH COOLEST GUIDANCE(FWC) FOR TUESDAY MORNING LOWS...
OR EVEN UNDERCUT THOSE VALUES TAKING INTO ACCOUNT INCREASED
EASTERLY FETCH. TUESDAY HIGHS MAY HAVE TO BE LOWERED FURTHER AS
WELL...WITH INCREASING EAST-NORTHEAST SFC WINDS AND LK MI EFFECT.

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

$$

12