[LeArc] Forecast Discussion : MLI@ 4/8/2003 3:32:52 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 080829
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
325 AM CDT TUE APR 8 2003

UPPER TROUGH FROM WI THROUGH CENTRAL IA WILL CONTINUE TO SHEAR AND
WEAKEN AS IT MOVES OVER THE REGION TODAY. REGIONAL RADARS
SHOW AREA OF -SN/--SN FROM NORTHEAST THROUGH CENTRAL IA WITHIN TROUGH
AXIS WHERE MID-HIGH LEVEL CLOUDS SEEDING LOW CLOUDS RESULTING IN
PCPN FALLING AS SNOW. ELSEWHERE...LOTS OF DRY AIR ALOFT 
PER WATER VAPOR PICS AND 00Z KDVN SOUNDING...THUS PCPN MAINLY SOUTH
OF DUBUQUE...TO CEDAR RAPIDS LINE FALLING AS DZ/FZDZ WITH SOME
SNOWFLAKES MIXED IN NEAR AND JUST SOUTH OF LEADING EDGE OF MID/HIGH CLOUDS.
WILL MONITOR RADAR TRENDS AND MAKE LAST MINUTE CALL ON HOW TO HANDLE PCPN
WORDING. INITIAL THOUGHTS ARE SOUTHEAST OF DUBUQUE...TO CEDAR RAPIDS
LINE TO GO WITH DZ/FZDZ EARLY THEN --SN WITH CHC -SN. 
APPEARS BEST CHC OF MEASURABLE SNOW WILL BE SOUTH TODAY NEAR VORT AXIS...BUT
STILL YET GENERALLY LESS THAN ONE HALF INCH USING VISIBILITY BASED
ESTIMATE. TEMPS TO STRUGGLE AGAIN TODAY WITH CLOUDS AND LLVL NORTHEAST
WINDS AND SIDE TOWARD LOW END OF GUIDANCE. 

TONIGHT...TROUGH WILL BE PASSING EAST EARLY ON. DECENT SUBSIDENCE ON
BACKSIDE SHOULD LEAD TO CLEARING SKIES...THOUGH MODEL RELH 
PROGS SUGGEST S/E ZONES MAY STAY CLOUDY MOST OF THE NIGHT WITH PARTIAL
CLEARING LATE. THUS...EXPECT NICE TEMP GRADIENT FROM NORTHWEST (COLDEST) TO
SOUTHEAST (WARMEST). SURFACE RIDGE AXIS TO APPROACH NORTHWEST ZONES
BY 12Z. VERIFICATION OF TEMPS AS OF 07Z JUST EAST OF RIDGE AXIS IN L/M 20S
SO WILL UNDERCUT GUIDANCE IN THE NORTHWEST BY FEW DEGS. 
WILL STAY NEAR LOW END OF GUIDANCE CENTRAL AND GO AT OR SLIGHTLY ABOVE IN
THE FAR SOUTH/EAST. DESPITE DRIER AIR FILTERING IN...WILL ADD MENTION
OF FOG IN THE NORTHWEST ZONES WITH SNOWMELT. 
 
WED-THU...QUIET PATTERN WITH SURFACE RIDGE AXIS SETTLING OVERHEAD.
GENERALLY SUNNY DAYS AND CLEAR NIGHTS. A FEW OF THE MODELS ARE SUGGESTING
LLVL NORTHEAST FLOW...HOWEVER AT LESS THAN 10 KTS...SO ATTIM 
TOO LIGHT FOR ANY POTENTIAL LAKE CLOUDS IMPACTING PORTIONS OF THE CWA...BUT
LATER SHIFTS WILL NEED TO MONITOR FOR ANY CHANGES. 
ALSO...WITH WET GROUND...CAN/T RULE OUT SOME FAIR WX CUMULUS DURING THE
AFTERNOON/S. TEMPS WILL BE TRICKY WITH LARGE MODEL DIFFERENCES (10-15 DEGS)
ON WED. DESPITE STRONG APRIL SUNSHINE...FEEL WET GROUND AND RIDGE AXIS
MAY IMPEDE WARMING SOME AND STAYED WITH BLEND OF LOWER END OF GUIDANCE ON
WEDNESDAY. SNOW SHOULD BE GONE BY THURSDAY...THUS WENT CLOSE TO
GUIDANCE ON MAXES. DECENT RADIATIONAL COOLING AND MOIST BOUNDARY LAYER DUE
TO SNOWMELT WILL LEAD TO POSSIBILITY OF FOG WED NIGHT INTO EARLY THU
NORTHERN HALF OR SO. 

EXTENDED...(FRI-MON)
NO CHANGES ATTIM. AVN/GFS PRINTING OUT LIGHT QPF WITH FRONT LATE FRI.
CURRENT FORECAST DRY ON FRI AND WILL HOLD OFF MENTION AND LET 
DAY SHIFT RE-EVALUATE POTENTIAL. 

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

$$

05