[LeArc] Forecast Discussion : MLI@ 5/9/2003 5:10:56 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 091006 CCA
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
425 AM CDT FRI MAY 9 2003

WARM FRONT INTO SOUTHERN SECTIONS OF CWA ATTIM...WITH WIDESPREAD 
PRESSURE FALLS OF 2-3 MBS OVER SOUTHERN WI AND MN LENDING 
SUPPORT TO MODEL SOLUTIONS WHICH BRING FRONT THROUGH THIS MORNING. 
WARM AIR SURGING IN EFFECTIVELY CHEWING AWAY AT THE 
LOW CLOUDS...THUS EXPECT MOST AREAS TO BE SUNNY/MOSUNNY BY MID 
MORNING. FOCUS THEN SHIFTS TO HIGH TEMPS AND POTENTIAL FOR SPOTTY LATE
AFTERNOON CONVECTION. WARM CONDITIONS LOOK ON TAP FOR TODAY...WITH
DECENT MIXING AND H85 TEMPS RANGING FROM 11C-17C. POTENTIAL 
FOR BREEZY CONDITIONS AS WELL WITH H85 WINDS PROGGED AROUND 30-35 KTS. 
WARM SURGE TO CAP ATMOSPHERE...AND WITH LITTLE FORCING DON/T SEE 
MUCH POTENTIAL FOR CONVECTION. THAT BEING SAID...KEPT A SLIGHT CHANCE
IN THE SOUTH FOR LATE THIS AFTERNOON WITH MODELS INDICATING 
THIS AREA CLOSE TO WEAK...STALLED OUT BOUNDARY WITH POTENTIAL TO 
APPROACH CONVECTIVE TEMPERATURES. THIS REGION ALSO IN DEEPER MOISTURE 
WITH SOMEWHAT HUMID CONDITIONS FOR EARLY MAY...WITH DEWPTS 
ROUGHLY FROM 65 TO 70 DEGS. HELD OFF ON HUMID WORDING THOUGH WITH 
SOUTHWEST BREEZE. SHORTWAVE TO EJECT OUT ACROSS NORTHERN MO AND CENTRAL IL
TONIGHT WITH 40-50 KT LLJ EXPECTED TO IGNITE ANOTHER ROUND
OF CONVECTION ESPECIALLY TO OUR SOUTH. WENT WITH LIKELY POPS IN SOUTH 
WITHIN THETA-E AXIS AND CLOSEST TO LIFT...TAPERING OFF TO LOW CHANCE POPS
IN FAR NORTH LATE. SPC HAS SLIGHT RISK BLANKETING ENTIRE CWA THROUGH
12Z. FEEL THOUGH THREAT IS MAINLY SOUTHERN ONE THIRD OR SO FOR LARGE HAIL 
WITH DAMAGING WINDS POSSIBLE IN FAR SOUTH CLOSER TO FRONTAL ZONE.
DEEP MOISTURE PRESENTS CONCERN FOR HEAVY RAIN. FORECAST SOUNDINGS 
SHOW PRECIPITABLE WATER INCREASING TO AROUND 1.5 INCHES...THUS INCLUDED
MENTION OF HEAVY RAIN IN SOUTH. HELD OFF THOUGH ON ANY HYDRO HIGHLIGHTS DUE
TO LIKELY FAST MOVEMENT. ALSO...SOME POTENTIAL FOR CONVECTION FURTHER SOUTH 
IN MO TO INHIBIT DEEPER MOISTURE RETURN.  

SATURDAY...INGREDIENTS APPEAR TO BE COMING TOGETHER FOR SIGNIFICANT 
OUTBREAK OF SEVERE WEATHER ACROSS CWA. THIS SYSTEM HAS LOTS OF DYNAMICS...SO 
WOULD EXPECT SOME SEVERE WEATHER EVEN IF WE END UP NOT SEEING MUCH IN THE 
WAY OF SOLAR INSOLATION/DESTABILIZATION. ETA/META NUDGING TRACK OF 
SURFACE WAVE SOUTHEAST A TAD...WITH TRACK FROM SOUTHWEST OF KIRKSVILLE MO 18Z 
SAT...TO SOUTH OF THE QUAD CITIES AT 00Z SUN...TO LAKE MI BY 06Z SUN...WITH 
THE CENTRAL PRESSURE DROPPING BY NEARLY 10 MBS! SPC HAS MODERATE RISK
FOR BASICALLY AREAS ALONG AND EAST OF THE MISSISSIPPI RIVER...WITH SLIGHT
RISK ENCOMPASSING REST OF THE AREA. INDICATIONS ARE THAT WE COULD
SEE POTENTIAL FOR SUPERCELLS AND TORNADOES...ESPECIALLY IN THE SOUTH...WITH
ONE OR TWO ON THE ORDER OF F3 TO LOW END F4...BASED ON INFLOW GUSTS
OF 17-24KTS FROM SOUTH/SOUTHWEST...TEMPS M80S AND DEWPTS NEAR 70 DEGS. 
WE/VE SEEN WHAT THIS BOUNDARY HAS DONE TO OUR SOUTH...SO THIS IS 
VERY CONCERNING...AND A POTENTIALLY LIFE THREATENING SITUATION. WILL ADDRESS 
THESE CONCERNS IN MORNING HWO. COULD VERY WELL SEE TWO CONVECTIVE MODES 
ON SAT...WITH SUPERCELLS INITIALLY...THEN SQUALL LINE AHEAD OF INCOMING COLD 
FRONT. 

STRONG GRADIENT KICKS IN LATE SAT NIGHT-SUN...WITH MUCH COOLER AIR INVADING.
KEPT CHANCE OF SHOWERS WITH POTENTIAL FOR DEF ZONE RAIN
DOWN THROUGH THE I-80 CORRIDOR ON BACKSIDE OF VIGOROUS SYSTEM SAT NIGHT.
COLD POOL DROPPING DOWN SUN YIELDS POTENTIAL FOR SHOWERS. 

NOT MUCH TIME TO LOOK BEYOND SUN...THUS NO CHANGES TO EXTENDED.  
 
DVN...
IA...NONE.
IL...NONE
MO...NONE.

$$

05