[LeArc] Forecast Discussion : MLI@ 5/8/2003 3:59:33 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 080856
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
350 AM CDT THU MAY 8 2003

MSAS AT 05Z HAS SURFACE LOW NEAR KIND WITH SURFACE RIDGE OVER ERN 
IA.  BACK EDGE OF WRAP AROUND STRATUS ALONG THE MS RIVER AND 
CREEPING E AT AROUND 10KTS.  SOME FOG DEVELOPING BETWEEN BACK EDGE 
OF STRATUS AND SURFACE RIDGE AXIS.  00Z UA ANALYSIS SHOWS TROUGH 
OVER SOUTHWEST U.S. WITH BROAD SWLY FLOW OVER REST OF COUNTRY.  
H3 100KT+ JET MOVING THROUGH BASE OF TROUGH.  H8 ANALYSIS SHOWS VERY 
MOIST AIR OVER THE SOUTHERN PLAINS/LOWER MS VALLEY WITH DEWPOINTS OF 
12 TO 16C COVERING A LARGE AREA.  

MODELS SEEM TO INTIALIZE OK WED EVENING.  BOTH THE ETA AND GFS WERE 
HAVING TROUBLE WITH THE JET STREAK MOVING THROUGH SOUTHERN CA.  
OBSERVATIONS ONLY SUPPORT 100KT SPEEDS WHILE GFS INITIALIZED STREAK 
AT 120KTS AND ETA ABOUT 10KTS STRONGTER.  SO FAR PROFILER IN NW NM
IS ONLY SHOWING 105KT WINDS...WITH MODELS ABOUT 30 TO 40 KTS 
STRONGER AT 06Z. 

SEVERE WEATHER AND HEAVY RAIN WILL TONIGHT AND AGAIN SATURDAY 
AFTERNOON AND EVENING WILL BE THE PRIMARY CONCERN THIS MORNING.
MODELS STILL SHOWING SOME DISCONTINUITY BETWEEN MODELS AND FROM RUN 
TO RUN.  INITIAL SYSTEM LIFTS OUT OF THE SOUTHERN PLAINS THIS 
AFTERNOON.  00Z GFS/ETA IN DECENT AGREEMENT THROUGH 00Z WITH SURFACE 
LOW OVER CENTRAL KS AND WARM FRONT EXTENDING EAST ACROSS 
CENTRAL/NORTHERN MO.  GFS THEN PULLS SURFACE LOW N INTO SERN SD 
WHILE ETA MOVED IT ENE.  HOWEVER...06Z META HAS COME MORE IN LINE 
WITH THE GFS...TAKING SFC LOW INTO NW IA BY 09Z.  

FOR TODAY WILL HAVE TO INCLUDE SOME PATCHY FOG WORDING MOST IN THE 
WEST WITH VSBYS AT SOME LOCATIONS DROPPING DOWN TO 1/4 MILE AT 
TIMES.  FOG SHOULDN'T LAST LONG WITH SELY WINDS PICKING UP BEHIND 
DEPARTING SURFACE RIDGE.  DRY EAST FLOW OVER CWA THIS MORNING WILL 
EAT AWAY AT PCPN MOVING IN FROM THE SW.  MODELS HOLD QPF OFF UNTIL  
THIS AFTERNOON WHICH LOOKS REASONABLE.  TONIGHT SHAPING UP TO BE A 
BUSY NIGHT WITH SEVERE HAIL AND HEAVY RAIN POTENTIAL.  WARM FRONT 
SHOULD BE OVER NRN MO BY 00Z  WITH MOIST UNSTABLE AIRMASS SOUTH OF 
THE FRONT. LLJ INCREASING TO 60-65KTS BY 06Z WILL TRANSPORT MOIST 
UNSTABLE AIR ACROSS THE FRONT...PROUDCING SOME COPIUS RAINFALL 
AMOUNTS...ESPECIALLY ACROSS THE NORTHERN CWA.  WILL HOLD OFF ON A 
FLASH FLOOD WATCH SINCE 06Z MODEL RUNS SUPPORTING A SHORT LIVED 
EVENT...WITH BEST FORCING SHIFTING NORTH OF CWA BTWN 06Z AND 09Z. 
WILL ISSUE AN ESF HIGHLIGHTING LOCALLY HEAVY RAINS TONIGHT AND SOME 
MINOR FLOODING POTENTIAL. 

WILL CONTINUE CHANCE POPS FOR FRIDAY WITH AIRMASS HAVING A CHANCE TO 
RECOVER DURING THE DAY.  GFS SHOWS WEAK S/W ENERGY MOVING THROUGH 
DURING THE AFTERNOON WHICH COULD TRIGGER SCT TSRA.  SEVERE WEATHER 
POTENTIAL CONTINUES TO LOOK OMINOUS FOR SATURDAY.  SYSTEM WILL TAP 
WARM HUMID AIR ALREADY IN PLACE JUST TO OUR SOUTH WITH ETA SHOWING 
3000+J/KG CAPES AADVECTING N AHEAD OF SURFACE LOW.  ETA/GFS HAVE 
SOME DIFFERENCES ON THE TRACK OF THE LOW...BUT BOTH MOVE IT THROUGH 
CWA DURING THE LATE AFTERNOON/EARLY EVENING AND SHOW IT DEEPING. 
SHOULD BE PLENTY OF ENERGY AND LOW LEVEL SHEAR TO SUPPORT SUPER CELL
DEVELOPMENT IN THE WARM SECTOR AND A THREAT OF MORE HEAVY RAIN ALONG 
AND NORTH OF THE LOW TRACK.

BIG COOL DOWN STILL ON TRACK AFTER SATURDAY EVENING WITH GFS 
SHOWING -2C H8 TEMPS AS FAR SOUTH AS I80 BY MONDAY MORNING.  

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

$$
DLF