[LeArc] Forecast Discussion : MLI@ 5/30/2003 3:12:08 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 302007
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
300 PM CDT FRI MAY 30 2003

...WE WILL BE TAKING A 21Z SOUNDING IN SUPPOR OF BAMEX...

STRONG SURFACE LOW OVER NORTH CENTRAL WI AT 18Z.  SURFACE TROUGH 
EXTENDS SOUTH THROUGH NERN INTO SOUTH CENTRAL IA.  BEHIND TROUGH 
TEMPS HAVE CLIMBED TO NEAR 90 OVER CENTRAL AND WRN IA. LEADING EDGE 
OF COOLER AIR AND STRONGER WIND FIELD WAS JUST ENTERING NORTHWEST IA.
SURFACE LOW WAS ASSOCTIATED WITH POTENT H5 TROUGH THAT WAS JUST 
CROSSING THE US/CANADIAN BORDER NR KINL AT 12Z. AFTER INITIAL 
ELEVATED CONVECTION EARLY THIS MORNING...PCPN HAS BEEN NIL...OTHER 
THAN NR VORT CENTER OVER NRN MN AND WI.  HOWEVER...AIRMASS OVER ERN 
IA/NRN IL IS STARTING TO DESTABALIZE WITH 19Z LAPS CAPES RANGING 
FROM AROUND 2000 J/KG IN NE MO TO AROUND 1200 J/KG IN NW IL.  
LOOKING OUT THE WINDOW...CU IS DEVELOPING...BUT HAS NIL VERTICAL 
EXTENT. WILL HAVE TO WAIT AND SEE IF CONVERGENCE NR SURFACE TROF TO 
THE W WILL PROVIDE ENOUGH KICK TO GET CONVECTION GOING FROM THE MS 
RIVER E INTO THE EARLY EVENING HOURS.  IF CONVECTION GOES...THEN 
THERE IS ENOUGH LOW LEVEL SHEAR TO SUPPORT SUPERCELL DEVELOPMENT. 

A WIND ADVISORY WILL BE ISSUED FOR THE NORTHERN HALF OF THE CWA THIS 
EVENING.  STRONGER SURFACE PRESSURE GRADIENT WILL REACH NW CWA EARLY 
THIS EVENING THEN SPREAD E INTO NORTHERN ILLINOIS.  STRONGEST WINDS 
WILL BE SUPPORTED BY DEEP MIXING EARLY ON...THEN WINDS SHOULD 
SUBSIDE SOME BY MIDNIGHT AS LOW LEVELS COOL...REDUCING MOMENTUM 
TRANSFER. SHRA/TSRA NR VORT CENTER ENTERING NRN WI THIS AFTERNOON 
SHOULD STAY N AND E OF CWA BASED ON TRACK OF THE VORT...SO WILL KEEP 
THE OVERNIGHT HOURS DRY.  MAV TMPS LOOK REASONABLE FOR OVERNIGHT 
LOWS.  SATURDAY THROUGH SUNDAY AFTERNOON WILL BE DRY AND COOL WITH 
HIGH PRESSURE SETTLING IN OVER AREA.  THE COOLEST TEMPS WILL BE 
REALIZED SUNDAY MORNING.  MID 40S OVER SOUTHERN CWA WILL BE CLOSE TO 
RECORD LOWS AT KBRL /44 1972/.  OTHER RECORDS...IN THE MID/UPPER 30S 
OVER CENTRAL AND NRN CWA...WILL BE A CATEGORY OR TWO BELOW EXPECTED 
MINS.  GFS MOVES ANOTHER WEAK SYSTEM THROUGH CWA SUNDAY NIGHT AND 
MONDAY AND WILL CONTINUE MENTION OF TSRA.  AT THIS TIME IT LOOKS 
LIKE THE BEST CHANCE WILL BE SOUTH WITH GFS TRACKING SURFACE 
LOW/INVERTED TROUGH THROUGH MO.

IN THE EXTENDED LONGRANGE MODELS CONTINUE TO POINT TOWARD A BROAD 
MID LEVEL TROUGH INTENSIFYING OVER THE CENTRAL U.S. THROUGH THE 
PERIOD.  THE GFS IS THE MOST AGRESSIVE CLOSING OFF AN H5 LOW OVER 
NRN IL BY FRIDAY.  ALL THIS POINTS TO COOLER THAN NORMAL WX.  TIMING 
ISSUES MAKE IT DIFFICULT TO PIN DOWN PCPN THREATS TO PARTICULAR DAY 
AND WILL HAVE TO CARRY LOW CHANCE POPS THROUGH THE PERIOD.


DVN...
IA...WIND ADVISORY THIS EVENING ALONG AND NORTH OF INTERSTATE 80. 
IL...WIND ADVISORY THIS EVENING ALONG AND NORTH OF INTERSTATE 80. 
MO...NONE.

$$

DLF