[LeArc] Forecast Discussion : MLI@ 2/5/03 4:59:39 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 051107
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
507 AM CST WED FEB 5 2003

SYNOPTIC PICTURE THIS MORNING SHOWS BROAD 500MB TROF OVER MUCH OF
THE U.S...WITH A TROF EXTENDING FROM A HUDSON'S BAY LOW INTO THE
DAKOTAS.  AT THE 300MB LEVEL...A LARGE 135KT JET EXTENDS FROM KANSAS
TO OFF THE VIRGINIA COAST.  AT THE SURFACE A 1027MB HIGH IS OVER THE
FORECAST AREA...WITH A WEAK LOW IN NORTH DAKOTA.

THE PRIMARY FORECAST CONCERNS THIS PACKAGE ARE THREE EVENLY SPACED
COLD FRONTS OVER THE NEXT 7 DAYS...RIDING DOWN FROM CANADA ON A
NORTHWEST FLOW.  THE FIRST FRONT WILL BE THURSDAY MORNING...THE
SECOND ON SATURDAY...AND THE THIRD ON MONDAY.  MOISTURE WILL BE
LIMITED...WITH THE MAIN IMPACT BEING TO KEEP TEMPERATURES ON THE
COLD SIDE. FOR THE FIRST TIME ALL YEAR WE HAVE A GOOD SNOW COVER...
ALBEIT THIN IN PLACES...ACROSS MUCH OF THE UPPER MIDWEST...AND THIS
WILL HAVE A CHILLING AFFECT ON TEMPERATURES WITH OUR NORTHWEST FLOW.

THE SHORT-TERM MODELS AGREE ON THE FIRST COLD FRONT MOVING THRU DVN
NEAR 10Z OR 11Z THURSDAY.  THE 135KT JET TO OUR SOUTH WILL LIFT
NORTH OVERNIGHT TONIGHT TO A POSITION OVER THE FORECAST AREA
THURSDAY.  A SECOND JET OF SIMILAR STRENGTH WILL MOVE INTO THE
SOUTHERN PLAINS...RESULTING IN JET COUPLING OVER MISSOURI.  THE
BEST 700MB VV'S AND 300MB DIVERGENCE WILL BE ACROSS MISSOURI INTO
CENTRAL AND SOUTHERN ILLINOIS TONIGHT AND THURSDAY...WITH A GOOD
CHANCE OF THE PRECIP...IN THE FORM OF SNOW...EXTENDING INTO
SOUTHERN PORTIONS OF THE FORECAST AREA.  A FEW TENTHS OF AN INCH
SOUTH ARE POSSIBLE LATE TONIGHT AND EARLY THURSDAY SOUTH...WITH A
DUSTING AT BEST CENTRAL AND NORTH.  FORCING AHEAD OF A SHARP 500H
TROF MOVING OVERHEAD THURSDAY NIGHT COULD PROVIDE SOME ADDITIONAL
LIFT ACROSS THE FORECAST AREA ON THURSDAY.

THE MEDIUM-RANGE MODELS AGREE ON THE NEXT COLD FRONT...SEMI-BACKDOOR
IN CHARACTER...ON SATURDAY...WITH A BROAD 500H TROF FOLLOWING
SATURDAY NIGHT.  THE THIRD FRONT...BACKDOOR IN CHARACTER...WILL
FOLLOW ON MONDAY.  MOISTURE WILL AGAIN BE LIMITED WITH THESE
SYSTEMS.

WILL STAY CLOSE TO CURRENT FORECAST...WITH SMALL TWEAKS TO
TEMPERATURES ON A FEW DAYS.  MAIN THEME WILL BE CONTINUED
SEASONABLY COLD WEATHER...WITH SEVERAL CHANCES TO PROVIDE SMALL
AUGMENTATIONS TO OUR MAINLY THIN SNOW COVER. 20 INCH SOIL
TEMPERATURES ARE STILL RUNNING AROUND 32 DEGREES DUE TO LACK OF A
DEEPER COVER IN MOST AREAS SO FAR THIS WINTER.


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

$$

REA