[LeArc] Forecast Discussion : MLI@ 2/11/03 4:23:11 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 112227
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
427 PM CST TUE FEB 11 2003

SYNOPTIC PICTURE THIS AFTERNOON SHOWS TROF AT 500MB PASSING OVER THE
FORECAST AREA.  AT THE SURFACE A STRONG COLD FRONT EXTENDS FROM
DUBUQUE TO CEDAR RAPIDS TO WEST OF OTTUMWA.  WINDS ARE 30 TO 40 MPH
BEHIND THIS FRONT. A VERY STRONG FALL-RISE PRESSURE COUPLET PASSING
THROUGH CEDAR RAPIDS AND INDEPENDENCE IS PRODUCING GUSTS TO 60
MPH.  VERY UNSTABLE LAPSE RATES BETWEEN THE SURFACE AND 850MB ARE
PRODUCING THUNDER.  AROUND AN INCH OF SNOWFALL IS FALLING JUST
AHEAD OF THE FRONT...NORTH OF A LINE FROM CEDAR RAPIDS TO
MAQUOKETA. THE RESULT IS BLOWING SNOW...AND NEAR WHITE

THE PRIMARY FORECAST CONCERN THIS PACKAGE IS IN THE FIRST FEW
HOURS...WITH THE HIGH WINDS.  SECOND IS A WARM FRONT AND LOW THAT
WILL PASS TO OUR SOUTH IN THE THURSDAY NIGHT/FRIDAY TIME FRAME...
PRODUCING A CHANCE OF PRECIP SOUTH.  500MB TROF IN THE SUNDAY TIME
FRAME COULD PRODUCE SOME LIGHT PRECIP.  MAIN SIGNAL OVER THE NEXT
SEVERAL DAYS IS A SWITCH FROM NORTHWEST TO ZONAL FLOW IN THE
THURSDAY NIGHT TIME FRAME...WITH MODERATING TEMPERATURES.

THE SHORT-TERM MODELS AGREE ON KICKING THE COLD FRONT SOUTHEAST
BY MIDNIGHT.  A WARM FRONT DEVELOPS ACROSS MISSOURI THURSDAY NIGHT...
AND REMAINS NEARLY STATIONARY THRU FRIDAY INTO FRIDAY NIGHT...
BEFORE BEING KICKED OUT TO THE EAST BY A LOW MOVING UP ALONG THE
FRONT SATURDAY MORNING.  PRECIP WILL BE MORE LIKELY SOUTH THROUGH
THE PERIOD.  FREEZING RAIN IS POSSIBLE THURSDAY NIGHT AND FRIDAY
MORNING.  THE MEDIUM-RANGE MODELS DISAGREE ON ONE OR MORE 500MB TROF
IN THE SATURDAY-SUNDAY TIME FRAME...WITH THE ONLY AGREEMENT BEING
ON A TROF AXIS SUNDAY.  TUESDAY WILL SEE A COLD FRONT.

WILL STAY CLOSE TO CURRENT FORECAST.  CONCERNING SUNDAY'S 500MB TROF
AND TUESDAY'S COLD FRONT...UNCERTAINTY AS TO PRECIP WITH THESE
FEATURES IS HIGH...SO PRECIP WILL NOT BE MENTIONED AT THIS TIME.

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

$$

REA