534 
FXUS63 KIWX 171920
AFDFWA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
213 PM EST FRI MAR 17 2000

FORECAST PROBLEM IS PRECIP CHC/TYPE FOR LATE SAT AND INTO SUN...

CURRENT FCST ON TRACK WITH TEMPS IN MID 30S MOST AREAS...EXCEPTION
IS WHERE SOME LK EFFECT CLDS LINGER. THESE CLDS SHOULD DISSIPATE AS
ANTICYCLONIC FLOW AND DRY AIR MASS DOMINATE THIS EVENING.  SO WL GO
WITH MSTLY CLR SKIES TONIGHT.  AS WINDS DIMINISH WE SHOULD DECOUPLE
AND SEE LOWER TEMPS THAN LAST NIGHT.  SO WL GO WITH AROUND 20.

DRY AIR MASS SEEN ON TIME HGT CROSS SECTION DOMINATES FOR THE DAY
ON SATURDAY. TEMPS SHOULD REBOUND INTO THE MIDDLE 40S AS THE WINDS
VEER AROUND TO A MORE SOUTHEASTERLY DIRECTION.

MODELS ARE IN AGREEMENT FOR THE FIRST 24 HRS...THEN AVN SOLN
DIVERGES.  AVN CLOSES OFF OPEN WAVE AND THEN PROGRESSES SYSTEM INTO
OH VALLEY BY DAY 3...LOOKS A LOT MORE IMPRESSESIVE TO OUR SOUTH THAN
THE ETA AND NGM.  IF AVN SOLN OCCURS THE GULF WL BE CUT OFF FROM THE
GT LKS REGION.  MEANWHILE THE NGM IS SLOWER THAN ETA IN BRINGING THE
MOISTURE CONVERGENCE INTO THE AREA. GIVEN THE SYSTEM IS STILL WELL
TO THE WEST...AND THAT THERE IS ALREADY A CUT-OFF IN THE SOUTH...I
LIKE THE SLOWER SOLN AND WL NOT INTRODUCE ANY PRECIP UNTIL LATE SAT
EVE. GIVEN THE TEMPS WL GO WITH SNOW TO START. TEMP PROFILE
SUGGESTS A CHG OVER TO RAIN FOR SUN.

FOR MONDAY...WL LEAN AWAY FROM THE AVN SOMEWHAT AND DOWNPLAY THE
PRECIP A BIT GIVEN THE PREVIOUS RUNS AND THE SHORTER RANGE MORE
BELIEVABLE DYNAMICS. AS FOR TEMPS MON AND TUES SHOULD BE WARMER AS
FLOW REMAINS PACIFIC IN ORIGIN.

THE UKMO IS MOST PROGRESSIVE WITH SFC FEATURE ON TUES...WITH A
998MB LOW IN SE KS. EVEN IF THIS SOLN IS CORRECT PRECIP SHOULD HOLD
OFF UNTIL CLOSER TO MID WEEK.

FAN AND FWC CLOSE TONIGHT AND REASONABLE. FOR TOMORROW THE WARMER
FWC IS BETTER GIVEN ABUNDANT SUN AND SE FLOW.

.IWX...NONE.

JLA