[LeArc] Forecast Discussion : MLI@ 2/27/03 5:50:51 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 272339
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
539 PM CST THU FEB 27 2003

RUNNING BEHIND. SYNOPTIC PICTURE LATE THIS AFTERNOON SHOWS WEAK
SURFACE RIDGE STILL EXTENDING FROM AN EASTERN HIGH BACK ACROSS THE
AREA. AT 500MB THE FLOW IS ZONAL...WITH A SHORT WAVE PRODUCING
LIGHT SNOW ACROSS NORTHERN MISSOURI INTO SOUTH CENTRAL ILLINOIS.

THE PRIMARY FORECAST CONCERNS ARE THREE-FOLD. FIRST IS A DISTURBANCE
IN THE FRIDAY NIGHT/SATURDAY TIME FRAME...MOVING OUT OF KANSAS.
SECOND IS A COLD FRONT SUNDAY MORNING...AND THIRD A COLD FRONT MONDAY
NIGHT. THE MODERATELY ZONAL SPLIT FLOW AT 500MB CURRENTLY OVER THE
AREA WILL BECOME NORTHWEST MONDAY NIGHT AFTER THE SECOND COLD
FRONT...BUT WILL REVERT TO ZONAL MID WEEK.  THE MAIN THEMES OVER THE
NEXT SEVEN DAYS WILL BE THICKNESSES THAT ARE LOW ENUF FOR PRIMARILY
SNOW CHANCES...AND SEASONABLY COOL WEATHER WITH A FAIR AMOUNT OF
CLOUD COVER.

THE AVN AND NGM INITIALIZED WELL THIS MORNING...BUT THE ETA HAD
PROBLEMS WITH HEIGHTS AND 500MB AND 700MB OUT WEST...BEING TOO DEEP
WITH A NEVADA LOW AND NOT DEEP ENUF WITH THE KANSAS WAVE.

THE SHORT-TERM MODELS AGREE ON THE CHANCE FOR LIGHT SNOW SOUTH
FRIDAY NIGHT INTO SATURDAY...AS A WEAK 500MB SHORT WAVE AND VORT MAX
MOVE OVER THE AREA...ALONG WITH AN INVERTED SURFACE TROF.  THE
MODELS ARE ALSO CLOSE ON COLD FRONT PASSAGE 09Z-12Z SUNDAY MORNING...
WITH THE ETA BEING THE FASTEST AND THE AVN THE SLOWEST. CHANCE POPS
FOR SNOW WILL BE NEEDED LATE SATURDAY NIGHT AND SUNDAY MORNING. THIS
FRONT WILL BRING ONLY A SHORT PUNCH OF COLD AIR.  THE BIGGER PUNCH
WILL BE WITH A COLD FRONT MONDAY NIGHT...THAT THE MEDIUM-RANGE
MODELS ALL AGREE ON FOR THE MOST PART...SAGGING ACROSS THE AREA AND
BRINGING IN A MUCH BROADER COLD AIR MASS...ALONG WITH SIGNIFICANT
CLOUD COVER AND A CHANCE OF SNOW...POSSIBLY SOME RAIN SOUTH.

WILL STAY CLOSE TO CURRENT FORECAST....MAKING MINOR ADJUSTMENTS TO
PERIODS FOR WHICH SNOW CHANCES EXPECTED.

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

$$

REA