[LeArc] Forecast Discussion : MLI@ 4/5/2003 6:04:32 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 060001
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
601 PM CST SAT APR 5 2003

SYNOPTIC PICTURE LATE THIS AFTERNOON SHOWED A WEAK RIDGE AT 500MB
OVER THE REGION...WITH A STRONG SHORT WAVE DEVELOPING OVER UTAH.  AT
THE SURFACE...HIGH PRESSURE WAS BEGINNING TO SHIFT NORTHEAST INTO
THE GREAT LAKES...AS A LOW MOVED OUT OF THE FRONT RANGE INTO
NORTHEAST NEW MEXICO.

THE PRIMARY FORECAST CONCERN THIS EVENING IS THE LATE WINTER STORM
BEARING DOWN ON US FOR THE SUNDAY NIGHT/MONDAY TIME FRAME.

THE SHORT-TERM MODELS ARE IN MODERATELY GOOD AGREEMENT ON THE
SYSTEM...WITH THE PRIMARY CHANGE IN THE LAST ONE OR TWO RUNS BEING
TO SLOW THE SYSTEM DOWN A BIT.  THE SURFACE LOW MOVES EAST ALONG
THE MISSOURI-ARKANSAS LINE SUNDAY EVENING...AND EAST TO EVV BY 12Z
MONDAY.  THE 500MB CLOSED LOW...ON THE OTHER HAND...SLOWS UP AND
TURNS INTO A SHARP OPEN TROF SUNDAY NIGHT AND MONDAY...AND DOESN'T
EXIT TO THE SOUTHEAST UNTIL 18Z TUESDAY.  DYNAMICS ARE STRONG FOR
THIS SYSTEM...WITH THE AVN AND NGM HAVING GOOD VV'S AND 300MB
DIVERGENCE FROM 18Z TO 06Z...STARTING EARLIER IN BRL...AROUND 12Z...
AND ENDING LATER IN DBQ...AROUND 12Z MONDAY.  THE ETA IS THE MOST
AMBITIOUS IN KEEPING DYNAMICS IN THE AREA...ALL THE WAY THROUGH
MONDAY. ISENTROPIC LIFT IS ALSO QUITE STRONG FROM 18Z SUNDAY TIL 12Z
MONDAY. MODEL QPF IS IN MODERATE AGREEMENT WITH .60 TO .75 INCHES OF
WATER EQUIVALENT PRECIP EXPECTED CENTRAL AND NORTH...AND A BIT LESS
SOUTH.  THE VORT MAX IS NOW PROGGED TO TRACK A LITTLE FURTHER
NORTH...FROM OTM TO CLINTON TO JUST SOUTH OF RFD...WHICH WOULD FAVOR
THE NORTH FOR BOTH QPF AND SNOW.

BROUGHT DOWN AMOUNTS A BIT IN WATCH AREA...ESPECIALLY SOUTH...DUE
TO LOSS FROM RAIN AT ONSET...WARM GROUND...AND RELATIVELY WARM TEMPS
IN THE LOWER LEVELS...WHICH SHOULD PRODUCE A MAINLY WET SNOW FROM I-
80 SOUTH...WITH A DRIER SNOW NORTH.  FOR FUTURE CONSIDERATION...
AFTER 00Z MODEL RUNS COME OUT...FORECAST AMOUNTS...BASED ON VORT
TRACK...MAY NEED TO GO UP A LITTLE ACROSS THE NORTHERN TIER...AND
DOWN A LITTLE CENTRAL AND SOUTH.  STORM ACROSS THE LOWER MISSISSIPPI
VALLEY...ASSOCIATED WITH SURFACE LOW...ALSO BEARS WATCHING...AS
MAY HAVE POTENTIAL TO ROB MOISTURE FROM OUR FORECAST AREA.


.DVN...
IA...WINTER STORM WATCH SUNDAY EVENING THROUGH MONDAY
IL...WINTER STORM WATCH SUNDAY EVENING THROUGH MONDAY
MO...WINTER STORM WATCH SUNDAY EVENING THROUGH MONDAY

$$

REA