[LeArc] Forecast Discussion : MLI@ 2/15/03 3:27:02 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 150936
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
337 AM CST SAT FEB 15 2003

WINTER STORM IN PROGRESS OVER ALL BUT FAR NORTHERN CWA EARLY THIS 
MORNING....BUT EVENG THERE SHOULD BE SEEING MUCH BLOWING SNOW. AREA 
RADARS SHOW NEARLY STATIONARY EAST TO WEST BAND ALONG INTERSTATE 80 
WHERE ISENTROPIC LIFT GREATEST. DRY NE FLOW HAS WON OUT FURTHER 
NORTH IN ADVISORY AREA. IN SOUTH...PRECIP HAS CHANGE TO SLEET AND 
SNOW WITH CONVECTIVE ELEMENTS STREAMING NE ON AREA 88DS. MAIN 
FORECAST CHALLENGE IS QUANTITY...COVERAGE AND TIMING OF ADDITIONAL 
SNOWFALL TODAY INTO EVENING.

WELL DEFINED CIRCULATION ON 88D MOSAIC AND PROFILERS SHOWING UP IN 
SE NEBRASKA WHILE SW FLOW WITH IMBEDDED VORT MAXIMA AND CONVECTIVE 
CLUSTERS SEEN STREAMING TOWARD NORTHERN MO. H85 WARM FRONT AT 00Z 
APPEARS TO BE ALONG IA/MO BORDER WITH LOW NORTH OF MKC. MAIN SURFACE 
LOW INDICATED BY MSAS OVER FAR SW MO AT 08Z. METARS SHOWING MODERATE 
SNOW IN IN DEFORMATION ZONE IN EASTERN NEB AND WESTERN IA WITH MAIN 
H5 TROUGH AXIS STILL UPSTREAM EXTENDING FROM WESTERN NEBRASKA TO NM. 
MODELS NOW IN CLOSE AGREEMENT WITH SLOW MOVING TROUGH AND H85 LOW 
MOVING SLOWLY SE. RESULT WILL BE CONTINUED SNOW THROUGH DAY ALONG 
AND SOUTH OF I-80 AS SLOW MOVING VORT MAX MOVES E-SE ALONG AND NORTH 
OF H85 BAROCLINIC BAND. HEAVIEST AMOUNTS TO BE BETWEEN HIGHWAY 34 
AND I-80 THROUGH MIDDAY...THEN FORCING AND QPF FAVORS SOUTH OF 
HIGHWAY 34 AFTERNOON INTO EARLY EVENING. DO NOT SEE MUCH ADDITIONAL 
SNOW ALONG NORTHERN TIER OF COUNTIES AND WILL LIMIT CURRENT ADVISORY 
TO MORNING HOURS...ALTHOUGH NE WINDS COULD KEEP SOME BLOWING AND 
DRIFTING SNOW THERE. ALONG I-80 CORRIDOR WILL GO WITH ADDITIONAL 1 
TO 3 INCHES...KEEP SE IA/NE MO AND W CENTRAL IL ZONES UP INTO 4 TO 6 
RANGE TODAY WITH TOTALS AS HIGH AS 6 TO 9 INCHES. COULD BE HIGHER 
BUT WITH SUCH STRONG WINDS...THINK CHARACTER OF SNOW WILL BE MORE 
COMPACTED AND DIFFICULT GET WIDESPREAD DEEPER COVERAGE. DRIER AIR 
WILL WIN OUT BY LATE AFTERNOON WITH LIFT LINGERING OVER ONLY FAR 
SOUTH. WILL THUS END MEASURABLE SNOW NORTH OF HIGHWAY 34 BY MID 
AFTERNOON...BUT CONTINUE ACCUMULATIONS TO SOUTH INTO EVENING HOURS. 
TIGHT NORTH TO SOUTH PRESSURE GRADIENT WILL KEEP WINDS STRONG WITH 
BLOWING SNOW THROUGH MUCH OF DAY UNTIL GRADIENT RELAXES. 

HAVE ADJUSTED WINTER WEATHER ADVISORY TO ONLY MORNING HOURS FOR 
NORTH WHERE SNOW EVENT MAINLY OVER BUT BLSN COULD CONTINUE TRAVEL 
PROBLEMS. WINTER STORM WARNING LOOKS GOOD OVER CURRENT AREA...EXCEPT 
HAVE TRIMMED BACK TO DAY ONLY FOR ALL BUT FAR SOUTHERN GROUPS WHERE 
SNOW TO CONTINUE INTO EARLY EVENING. FALLING SNOW AND COLD AIR 
ADVECTION IN NE FLOW TO KEEP TEMPERATURES NEARLY STEADY THROUGH DAY 
AND STAYED CLOSE TO OR JUST BELOW GUIDANCE. 

BEYOND TODAY...COLD RIDGE OF HIGH PRESSURE SUNDAY NIGHT EXTENDING SW 
OUT OF GREAT LAKES TO RESULT IN IDEAL RADIATIONAL COOLING AND WITH 
FRESH DEEP SNOW COVER HAVE CUT MINS WAY BELOW GUIDANCE CLOSER TO 
ZERO. MEDIUM RANGE GUIDANCE SHOWING SOME CHANGES TO TIMING OF LATE 
WEEK SYSTEM BUT WITH LIMITED TIME DUE TO BUSY AND COMPLEX SHORT TERM 
CHALLENGES WILL NOT TWEAK GOING OUT PERIODS.     

.DVN...
IA...WINTER STORM WARNING CONTINUES THIS MORNING ALONG 
COUNTIES ROUHGHLY ALONG HIGHWAY 30 CORRIDOR. HIGHWAY 30 SOUTH TO 
HIGHWAY 34 CONTINUED THROUGH TODAY...FROM HIGHWAY 34 SOUTH CONTINUED 
THROUGH THIS EVENING. WINTER WEATHER ADVISORY THROUGH MIDDAY ALONG 
THE HIGHWAY 20 CORRIDOR INCLUDING JACKSON COUNTY.
IL...WINTER STORM WARNING FOR CONTINUES FOR TODAY FROM HIGHWAY 20 
SOUTH TO ROUGHLY HIGHWAY 34. FROM HIGHWAY 34 SOUTH...WINTER STORM 
WARNING TODAY INTO THIS EVENING. WINTER WEATHER ADVISORY THIS 
MORNING ALONG THE HIGHWAY 20 CORRIDOR IN FAR NORTHWEST IL. 
MO...WINTER STORM WARNING CONTINUES FOR TODAY THROUGH THIS EVENING.

$$

DLS