[LeArc] Forecast Discussion : MLI@ 4/22/2003 4:25:38 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 220921
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
421 AM CDT TUE APR 22 2003

SOME QUIET WEATHER ACROSS THE REGION TODAY WITH THE SURFACE RIDGE
JUST TO THE WEST OF THE CWA.  WINDS ARE QUITE LIGHT ACROSS CENTRAL
IA...AND IF THE DRY GROUND HADN'T SOAKED UP ALL THAT RAIN YESTERDAY
WE'D HAVE LOTS OF FOG THIS MORNING.  UPPER LEVELS INDICATING
THAT THE UPPER LOW EXITING RAPIDLY OFF TO THE NORTHEAST.  LOW CLOUDS
MOVED OFF WITH THE UPPER SYSTEM...AND HAVE BEEN CLEAR ACROSS ENTIRE
CWA SINCE BEFORE MIDNIGHT.  NEXT SYSTEM WELL SAMPLED MOVING ON SHORE
OVER NORTHERN CA.

MAIN CONCERNS THIS FORECAST INCLUDE TEMPS TODAY AND WEDNESDAY...AND
THE ONSET OF PRECIP FOR THURSDAY.

00Z MODELS APPEAR TO HAVE INITIALIZED OK...AND ARE IN GOOD
AGREEMENT THROUGH THE FORECAST PERIOD ON THE MAIN FEATURES.  BY
FRIDAY 12Z...AT 84 HOURS...BOTH AVN AND ETA HAVE THE UPPER LEVEL LOW
MOVING ACROSS THE MIDWEST WITHIN THE SAME STATE...WITH THE AVN A
LITTLE FARTHER NORTH THAN THE ETA.

TODAY MAIN CONCERN IS HOW WARM TO GO WITH TEMPERATURES.  NORTH FLOW
IS NOT ESPECIALLY CONDUCIVE TO WARMING FOR THIS AREA...AND DESPITE
APRIL SUNSHINE...TEMPS NOT TO GET MUCH WARMER THAN THEY DID OVER
CENTRAL IA MONDAY...AND HAVE GONE WARMER THAN AVN OR NGM MOS
GUIDANCE...BUT NOT AS WARM AS THE ETA MOS VALUES...AS HAVE SEEN ETA
OVERDO LOW LEVEL WARMING BEFORE.  SOME LINGERING MOISTURE OVER FAR
SOUTHERN AREAS IN THE GFS HAVE LED ME TO THINK THERE WILL BE A FEW
CU THERE THIS AFTERNOON...WHICH WILL ALSO LEAD TO COOLER TEMPS
THERE.  NOT TO BE MUCH VARIATION IN HIGH TEMPS THIS AFTERNOON.
TONIGHT TEMPS ALSO TRICKY...BUT WITH LOW LEVEL SOUTHEASTERLY FLOW
AND RIDGE MOVING OFF TO THE EAST...WE WONT RADIATE OUT TOO MUCH.
HAVE GONE A LITTLE WARMER THAN GOING FORECAST HAD.

WEDNESDAY...HIGH CLOUDS OUGHT TO START STREAMING OVER UPPER LEVEL
RIDGE AND INCREASING CLOUD COVER OVER CWA.  SOUTHEASTERLY FLOW NOT
STRONG ENOUGH TO CAUSE BIG TIME WARM-UP...AND ARE EXPECTING TO ONLY
JUST MIX TO 850 MB...SO HAVE GONE WARMER THAN GOING FORECAST.

HAVE GONE DRY WITH WEDNESDAY NIGHT FORECAST FOR NOW...BUT IT WILL BE
A NEAR THING WITH A NICE WARM AIR ADVECTION WING MOVING TOWARDS THE
AREA FROM THE SOUTHWEST.  HAVE GONE WITH SLIGHTLY SLOWER ETA
TIMING...BUT MORE BECAUSE THE AVN LOOKS A LITTLE TOO WET...AND IT
TAKES A LOT LONGER TO SATURATE THE LOWER LAYERS THAN THE AVN
TYPICALLY DOES. PRECIP SHOULD MOVE QUICKLY NORTH ACROSS THE SOUTHERN
HALF OF THE CWA DURING THE MORNING...AND HAVE GONE WITH PRETTY HIGH
POPS THERE FOR THURSDAY AND THURSDAY NIGHT.  NORTHERN HALF IS MUCH
CHANCIER AND WITH THERE STILL BEING SOME DIFFERENCE IN NORTH SOUTH
POSITION OF THIS UPPER LEVEL LOW...HAVE GONE WITH CHANCE POPS FOR
NORTHERN AREAS.   BY FRIDAY THE EXITING SYSTEM MOVING A LITTLE
SLOWER ON THIS RUN...AND HAVE EXPANDED FRIDAY PRECIP A LITTLE.

MADE NO CHANGES TO FRIDAY NIGHT THROUGH MONDAY TIME FRAME.

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

$$

LE