[LeArc] Forecast Discussion : MLI@ 5/13/2003 1:54:29 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 131854
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
155 PM CDT TUE MAY 13 2003

.SHORT TERM - THRU WED...
MAIN FOCUS WILL SHIFT TO SHRTWV CURRENTLY OVR THE NRN PLAINS.  SATL 
SHOWING DECENT CLOUD SHIELD AND PCPN PATTERN ACRS THE DAKOTAS.  
EXPECT ELEVATED CONVECTION TO DVLP OVERNIGHT AS THE SHRTWV DROPS 
SOUTH.  MODELS...PARTICULARLY THE ETA SEEM TO BE A BIT OVERDONE WITH 
QPF AMOUNTS ACRS IOWA DURING THE NEXT 8 TO 15 HOURS SPCLY SINCE RGNL 
SFC DWPNTS ARE ONLY IN THE 40S AND 50S.  HOWEVER FAIRLY GOOD JET 
DYNAMICS SHOULD RESULT IN WPRD PCPN PATTERN TO THE NORTH OF THE SFC 
WRMFNT.
 
SLGT RISK FOR LARGE HAIL ON WEDNESDAY.  THIS IS CERTAINLY NOT 
UNUSUAL IN WAA ZONE AHEAD OF SHRTWV DIVING SOUTHEAST.  QUESTION IS 
WILL LAPSE RATES BE STEEP ENUF?  BEST CHC FOR SVR WEATHER IS 
PROBABLY ACRS THE SRN PORTION OF THE FCST AREA SPCLY IF SFC WRMFNT 
LIFT A LITTLE NORTH AS AVN IS SUGGESTING.  STILL TOO MUCH 
UNCERTAINTY TO MENTION IN ZONES.   

.LONGER TERM - THU...
H5 LOW DROPS RIGHT ACRS OUR FCST AREA ON THU.  AS A RESULT CLOUDS 
WILL BE SLOW TO CLEAR AND TEMPS WILL BE ON THE COOL SIDE ON THU.  
HAVE GONE AT OR BLO GUIDANCE.  
      
.EXTENDED FCST - DAY 3 THRU 7...
MAIN FEATURE IS DEVELOPMENT OF STG SFC HI PRESSURE OVER THE GRTLKS 
WHICH EXTENDS INTO THE MID-MISSISSIPPI VLY.  THIS PATTERN IS 
PLAUSIBLE SINCE DEEP TROF DVLPS ACRS THE NRN PACIFIC COAST AND HI 
PRES DVLPS IN THE CONFLUENCE ZONE TO THE WEST OF A STG UPR TROF OVR 
THE CANADIAN MARITIMES.  STILL THINK A DRY AND SEASONAL WEATHER 
PATTERN IS EXPECTED FOR FRIDAY THRU MONDAY.

ONLY EXCEPTION TO THIS THINKING IS THE ECMWF AND 00Z MRF WHICH HINT 
AT A SHRTWV OVR THE LOWER MISSISSIPPI VLY BY 12Z SAT. THIS COULD 
PUSH ENUF MSTR N TO PRODUCE SHWRS IN OUR SRN CWA.  HOWEVER...THE 
LATEST AVN AND CANADIAN MODELS SUGGEST THAT THE SHRTWV WILL REMAIN S 
OF OUR AREA.  GIVEN THE STRENGTH OF THE SFC HI OVR THE GRTLKS WILL 
KEEP OUR FCST DRY THRU DAY 6.  WILL INTRODUCE SHWRS ON DAY 7 AS WRN 
US TROF FINALLY PUSHES INTO THE PRAIRIE STATES.  

$$

 BELLES