[LeArc] Forecast Discussion : MLI@ 3/3/03 4:35:45 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 032241
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
441 PM CST MON MAR 3 2003

RUNNING WAY BEHIND DUE TO IFPS...WWA...AND XNOW SUDDENLY ACTING UP
ON ME.

BRIEFLY...WEAK SYSTEM TO PULL OUT THIS EVENING BRINING AN END TO THE
SNOW. THIS ALLOWS COLD FRONT/TROF TO MOVE THROUGH AS DIRTY RIDGE
SKIRTS NORTH OF THE REGION.

SHOULD HAVE BEEN MORE PERSUASIVE YESTERDAY WHEN I WANTED TO GO WITH
A WATCH. NOW LEAD TIME ON THIS EVENT WILL BE NOTHING. ANYHOW
SIGNIFICANT SYSTEM TO MOVE THROUGH TUE/TUE NIGHT AND HAVE RAISED
HEADLINES FOR A WATCH. GULF WIDE OPEN ALLOWING VERY IMPRESSIVE
ISENTROPIC LIFT TO DEVELOP LATE TONIGHT. UKMET/ETA HAVE COME AROUND
MORE TO THE AVN SOLUTION ON PLACEMENT OF PRECIPITATION. DEPENDING ON
THE MODEL THERE ARE 2 TO 4 G/KG ADVECTING INTO THE AREA TUE/TUE
NIGHT. THIS COMBINED WITH IMPRESSIVE LIFT/FRONTOGENETICAL FORCING TO
ALLOW HEAVY SNOW TO DEVELOP. PARTIAL THICKNESSES SUGGEST A MIXTURE
FROM HIGHWAY 34 ON SOUTH INITIALLY BEFORE CHANGING OVER TO ALL SNOW
LATE TUESDAY. TEMPERATURES ALOFT IN THE CRITICAL RANGE TO ALLOW
DENDRITIC CRYSTAL GROWTH FOR THIS EVENT.  MODELS ALSO SHOWING
INSTABILITY ALOFT OVER THE CWFA TUE WHICH MAY LEAD TO MESOSCALE
BANDING OF THUNDER-SNOW. IF THIS OCCURS THERE WILL BE AREAS OF 7+
INCHES ALONG WITH THE GENERAL 4-7 THAT I AM CURRENTLY THINKING.
PRECIP TO SHUT OFF RAPIDLY AFTER MIDNIGHT TUESDAY NIGHT AND SHOULD
END BEFORE SUNRISE WEDNESDAY.

ANOTHER WEAK SYSTEM TO SKIRT JUST SOUTH OF THE CWFA ON WEDNESDAY.
LIFT/FORCING STRONG ENOUGH WITH H5 TROF ALOFT THAT SOME SNOW SHOULD
BE SEEN IN THE FAR SOUTH.

THINGS QUIET DOWN IN THE EXTENDED WITH 2 SYSTEMS TO AFFECT THE
AREA...ONE SATURDAY AND POSSIBLY ANOTHER ON MONDAY. EXTENDED 12Z
AVN SUGGESTS A POLAR VORTEX SINKING SOUTH IN TO THE GREAT LAKES
REGION AS A REX BLOCK DEVELOPS ALONG THE WEST COAST.

TEMPERATURES TO BE A CHALLENGE THIS WEEK. DESPITE MARCH SUN...SNOW
FIELD SHOULD HELP KEEP TEMPERATURES IN CHECK.

.DVN...WINTER STORM WATCH TUESDAY AND TUESDAY NIGHT.
IA...IAZ040>042-051>054-063>068-076>078-087>089-098-099.
IL...ILZ001-002-007-009-015>018-024>026-034-035.
MO...MOZ009-010.

$$

SF