[LeArc] Forecast Discussion : MLI@ 1/31/03 4:06:37 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 311016
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
416 AM CST FRI JAN 31 2003

COMPLEXITY OF FCST HAS ME RUNNING WELL BEHIND. BRIEFLY. CURRENT
SYSTEM HAS FINALLY SATURATED ATMOSPHERE ALLOWING PRECIP TO REACH
THE GROUND. ONCE SATURATED...PRECIP GOES FROM RAIN...TO SLEET...TO
SNOW ALL WITHIN AN HOUR. RADAR TRENDS SHOW PRECIP FALLING APART BUT
NEXT WAVE ASSOCIATED WITH LOW NOW MOVING INTO NORTHEAST IOWA. SNOW
AMOUNTS TO BE CUT BACK AS WELL. LIKELY TO ONLY SEE 1-2 WITH
ISOLATED 3 AMOUNTS. AS SUCH HAVE DROPPED MUCH OF ADVISORY AND ONLY
KEPT WHERE IT MIGHT VERIFY. PRECIP TO RAPIDLY SHUT OFF AFTER 15Z AS
BEST QG FORCING/OMEGA MOVES EAST OF THE FORECAST AREA.

TONIGHT RIDGE BUILDS ACROSS THE REGION WITH WINDS DROPPING OFF. NOT
TOTALLY SURE BUT SOME PATCHY FOG MAY DEVELOP AS TEMPERATURES
APPROACH DEW POINTS IN LIGHT WINDS. QUIET WX SATURDAY AS WAA
DEVELOPS. SATURDAY NIGHT COULD GET REAL INTERESTING. WEAK SURFACE
CONVERGENCE...COMBINED WITH NEUTRAL TO WEAK DOWNWARD MOTION...AND
WAA OVER COLD GROUND/SNOW COVER SHOULD CAUSE DENSE FOG TO DEVELOP.
ETA AND TO SOME EXTENT AVN DEVELOP A SATURATED LAYER FROM THE
SURFACE TO ABOUT 950 MB SATURDAY NIGHT. SUNDAY WAA COMBINED WITH
STEEP LAPSE RATES TO BRING A GOOD WARM UP. GIVEN STILL DAMP GROUND
SHOULD EASILY SEE 20 DEGREE SPREAD IN HIGHS ACROSS CWFA.

DUE TO DIFFICULT PERIOD 1...DID NOT TOUCH THE EXTENDED. GLOBAL
MODELS HAVE SLOWED SYSTEM DOWN BUT IT STILL LOOKS REAL INTERESTING
FOR EARLY NEXT WEEK. NEXT ARCTIC SHOT TO ARRIVE SECOND HALF OF NEXT
WEEK...RIGHT ABOUT THE TIME I THOUGHT IT WOULD 2 WEEKS AGO.

.DVN...WINTER WEATHER ADVISORY TIL 9 AM.
IA...IAZ040>042-051>054-066.
IL...ILZ001-002-007-009.
MO...NONE.

SF

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