[LeArc] Forecast Discussion : MLI@ 3/25/03 3:48:50 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 252144
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
344 PM CST TUE MAR 25 2003

AT MID AFTERNOON COLD FRONT WAS LOCATED ALONG THE OHIO RIVER
INTO NORTHERN AR.  A WEAK RIDGE OF HIGH PRESSURE WAS NOSING INTO
WESTERN IA.  LOTS OF POST FRONTAL CI/MID CLOUD STREAMING NE ACROSS
CWA THIS MORNING AND EARLY THIS AFTERNOON.  RADAR SHOWING SOME
RETURNS OVER THE FAR SOUTHEAST CORNER...BUT NONE OF IT IS REACHING
THE GROUND.  MID LEVEL TROUGH LOCATED JUST WEST OF CWA AT 12Z IS
PROGGED TO MOVE EAST OF THE MISSISSIPPI RIVER BY EARLY THIS EVENING
TAKING MID/HIGH CLOUDS OVER SERN CWA WITH IT. UPSTREAM OVER THE
NORTHERN PLAINS ANOTHER WEAK TROF WAS GENERATING SOME LIGHT PCPN
OVER OVER THE DAKOTAS.  MODELS ARE CONSISTENT IN MOVING THIS SYSTEM
THROUGH NRN IA/SRN MN OVERNIGHT.  AT LEAST THE NORTHERN HALF OF CWA
SHOULD SEE SOME MID CLOUDS ASSOCIATED WITH THIS SYSTEM MOVING IN
AFTER MIDNIGHT.  GFS APPEARS TO BE OVERDOING THE SOUTHERN EXTENT OF
THE LIGHT PCPN OVER THE NORTHERN PLAINS AROUND MID DAY. ONLY REPORTS
OF PCPN REACHING GROUND WERE OVER NORTH DAKOTA WITH SOME VIRGA
REPORTED AT KHON. WILL BE BUMPING UP MINS A LITTLE TONIGHT IN THE
NORTH WITH MID CLOUDS LIMITING TEMPERATURE DROP.

THINGS GET MORE INTERESTING BEGINNING WEDNESDAY AND CONTINUING
THROUGH DAY 7. ALL MODELS SHOW NICE WAA/ISENTROPIC LIFT ON A
STRENGTHENING LLJ IN WESTERN IA WED AFTERNOON/EVENING. SIGNALS
POINT TO POSSIBLE MCS DEVELOPMENT THAT MAY SKIRT AREAS NORTH OF
HIGHWAY 30 WED NIGHT INTO THURSDAY MORNING. DEVELOPING PLAINS
SYSTEM INCREASES LLJ ON THURSDAY BRINGING WARM CONDITIONS. MOISTURE
STILL A QUESTION BUT POTENTIAL BOUNDARY FROM NOCTURNAL MCS MAY BE
ENOUGH TO ALLOW SHRA/TSRA TO DEVELOP LATE THURSDAY. INSTABILITY IS
THE KEY FACTOR...AND MODELS STILL SEEM TO BE IN CATCH UP MODE.

SYSTEM ROLLS THROUGH THURSDAY NIGHT THROUGH SATURDAY. LIKE UKMET IN
BRINGING SURFACE LOW ACROSS CWFA. TEMPS SHOULD NOT BUDGE MUCH FRIDAY
AS CAA STRENGTHENS. BRIEF DRY PUNCH SHOULD CUT OFF PRECIP FOR A
WHILE FRIDAY BEFORE RESTARTING AS A RAIN/SNOW MIX IN THE AFTERNOON...
TURNING TO ALL SNOW LATE. DEFORMATION ZONE SETS UP FRIDAY
NIGHT/SATURDAY WITH ALL SNOW. POTENTIAL EXISTS FOR SOME
ACCUMULATION. QUIET WX AS RIDGE MOVES THROUGH SUNDAY BEFORE CLIPPER
SYSTEM AFFECTS THE AREA LATE MONDAY AND TUESDAY. LUCKILY PRECIP
SHOULD BE OF THE LIQUID VARIETY FROM THE CLIPPER SYSTEM.

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

$$

DLF/SF