[LeArc] Forecast Discussion : MLI@ 1/14/03 1:51:02 AM

Tue, 14 Jan 2003 01:51:02 -0600

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

FXUS63 KDVN 140800
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
155 AM CST TUE JAN 14 2003

.OVERVIEW...SWATH OF LIGHT SNOW AT 07Z EXTENDS FROM JUST NORTH OF
CEDAR RAPIDS TO NORTH OF PRINCETON.  PRECIPITATION MOVING EAST
SOUTHEAST AT 25 MPH.  LOCATIONS NORTH OF THIS AXIS BASED ON ASOS/AWOS
VISIBILITIES...RADAR DBZ AND ISOLATED REPORTS SUPPORT DUSTING TO JUST
OVER 1/2 INCH SO FAR.  AWIPS DISTANCE TIME FEATURE SUPPORTED BY
SATELLITE AND SFC PRESSURE SUGGEST PRECIPITATION WANE AND SLIDE EAST
BY 12Z WITH SOME LINGERING FLURRIES TIL MID MORNING.  UPPER AIR
ANALYSIS SHOWS GOOD RIDGING FOR CAA AND CLEARING SKIES NEXT 12-24
HOURS AS NEXT LOBE OF ARCTIC AIR MOVES IN.

...TIMING ENDING OF LIGHT SNOW NORTH AND CLEARING TODAY NEAR TERM
ISSUE AND NORTHERN EXTENT OF PRECIPITATION WITH NEXT SYSTEM MID WEEK
MOST NOTABLE FORECAST ISSUES...

.DIAGNOSIS AND DAY 1-3...ALL MODELS HAVING SOME PROBLEMS IDENTIFYING
BACK EDGE OF CLEARING TREND...WILL LEAN TOWARD NOWCAST TOOLS OF
SATELLITE AND PRESSURE RISES SUPPORTED BY TIMING MOVEMENT.  THUS
CLEARING MID TO LATE MORNING FROM N TO S.  TEMPS WITH SUNSHINE WILL
REMAIN SLIGHTLY ABOVE GUIDANCE AS DIABATIC HEATING AND ONLY MODERATE
CAA PROMOTE GOOD MIXING...SUPPORTING BRISK NW WINDS OF 15 TO 25 MPH
MOST AREAS BY EARLY AFTERNOON.  AS WINDS DECREASE AND CLEAR SKIES
TONIGHT...GOOD RADIATIONAL COOLING TO REMAIN BELOW GUIDANCE WHICH IS
5 DEGREES COOLER COMPARED TO LAST NIGHT...SEE NO REASON NOT TO SEE
MORE CATCH UP OF GUIDANCE.  THIS MEANS LOWS NEAR TO JUST ABOVE
ZERO...EVEN WITH LIMITED OR NO SNOWCOVER.   WEDNESDAY...INCREASING
HIGH CLOUDS DURING DAY WITH UKMET AND AVN UPPER AIR BOTH SUPPORTING
NORTHEASTERN EDGE OF SOME SNOW TO MAKE INTO SW 1/4 TO 1/3 OF CWA
WEDNESDAY NIGHT INTO THURSDAY MORNING. THIS HANDLED WELL IN CURRENT
PACKAGE AND PLAN NO CHANGES.  INTERESTING THAT ETA IS ODD MODEL WITH
EXTREME SOUTH SOLUTION AND NOT REASONABLE COMPARED TO OTHERS AND ALSO
PREVIOUS RUNS.  ROTATING SHORT WAVE AND UPPER TROUGH ON THURSDAY
SUPPORTS KEEPING FLURRIES WORDING NORTHERN AREAS.

.EXTENDED (FRI-MON)...NW FLOW CONTINUES WITH NEAR TO BELOW NORMAL
TEMPERATURES AND LIMITED CHANCE OF SIGNIFICANT PRECIPITATION.  UKMET
AND AVN-GFS SUGGEST BROAD UPPER SYSTEM OR TROUGH SATURDAY BUT LIMITED
FORCING AND MOISTURE TO WORK WITH SO WILL ADD ONLY FLURRIES...BUT
OTHER THAN THAT...LITTLE CHANGE TO CURRENT PACKAGE.

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

NICHOLS