[LeArc] Forecast Discussion : MLI@ 6/7/2003 4:47:43 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 072136
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
430 PM CDT SAT JUN 7 2003

UPPER LOW MARCHING EASTWARD INTO WESTERN IA WITH VORT MAX GENERATING AN AREA
OF SHOWERS AND SOME THUNDERSTORMS INTO CENTRAL IA ATTIM.
WEAK SURFACE TROUGH/CONVERGENCE AIDING ISOLD TO SCATTERED THUNDERSTORMS 
MAINLY IN FAR WESTERN ZONES...WITH ONE OR TWO AIRMASS THUNDERSTORMS
HAVING POPPED UP WITHIN THE LAST HOUR OR SO IN NORTHEAST MO. 

MAIN CONCERN IS WITH POPS/TEMPS NEXT FEW DAYS. 

UPPER LOW INTO WESTERN IA ATTIM WILL MOVE E/NE ACROSS THE REGION LATE TONIGHT
AND EARLY ON SUN. SOME CONCERNS THAT PCPN COVERAGE MAY DIMINISH SOME
AFTER SUNSET WITH LOSS OF HEATING...BUT HEALTHY LIFT WITH DECENT OMEGA...JET
SUPPORT AND PVA SUPPORT HIGH POPS. WITH MORE IN THE WAY OF CLOUDS WILL
GO SOME 3-5 DEGS ABOVE MINS OF THIS MORNING...WITH GUIDANCE IN THE BALLPARK. 

MODELS INDICATE POTENTIAL FOR DRY SLOT SUN MORNING ESPECIALLY IN THE SOUTH
AND WEST...AS UPPER LOW LIFTS THROUGH. DIFFICULT WORDING PCPN TYPE.
BELIEVE WE/LL SEE DEFORMATION ZONE WRAP BACK IN AROUND UPPER LOW AND AFFECT 
NORTHERN 1/2 OR SO DURING THE AFTERNOON. ELSEWHERE...WITH COLD POOL 
EXPECT SCATTERED SHOWERS. FOR THOSE WITH INTEREST IN THE AIR SHOW IN THE
QUAD CITIES...THINKING SHOWERS WILL SHUT DOWN AROUND OR SHORTLY 
AFTER 7 AM...THEN THERE SHOULD BE SOME DRY TIME BETWEEN 7 AM AND 11 AM BEFORE 
THE DEFORMATION ZONE WRAPS BACK IN AROUND THE LUNCH HOUR. 

NEXT SHIFT MAY NEED TO CONSIDER ADJUSTING PCPN TYPE ON SUN TO MORE STRATIFORM 
RATHER THE CONVECTIVE...AND MAY NEED TO INCREASE POPS SUN EVENING
ESPECIALLY NORTHERN 1/2 UNTIL DEFORMATION ZONE EXITS. PCPN TRENDS WILL TELL.
KEPT PREVIOUS SHIFTS IDEA OF UNDERCUTTING GUIDANCE BY A CAT OR SO 
WITH CLOUDS AND RAIN. POTENTIAL IS THERE FOR SOME FOG SUNDAY NIGHT WITH 
ANY CLEARING BUT GRADIENT APPEARS TO TIGHTEN SOME ALLOWING FOR WINDS TO STAY 
UP...AS IT LOOKS RIGHT NOW...SO HAVE REMOVED MENTION.  

MONDAY LOOKS RELATIVELY QUIET WITH WEAK RIDGING AT THE SURFACE. PCPN CHCS
INCREASE LATE MONDAY NIGHT AND TUE AHEAD OF NEXT FRONT. 

EXTENDED (WED-SAT)...TOUGH FORECAST WITH FRONTAL POSITIONING CRITICAL. 07/12Z 
GFS EXTENSION CONTINUES RECENT MODEL TRENDS OF PUSHING FRONT FURTHER SOUTH
ACROSS MO ON THU. SEVERAL CONVECTIVE COMPLEXES WILL DEVELOP AND ROLL
EASTWARD ALONG EAST-WEST FRONTAL ZONE. OUTFLOW BOUNDARIES WILL 
ADD TO COMPLEXITY OF FORECAST AS THEY WILL MOST LIKELY IMPEDE NORTHWARD 
PROGRESS OF FRONT. THUS...WHEN TO INTRODUCE PCPN IS MAIN QUESTION.
THURS LOOKS LIKE MOST OF THE PCPN WILL BE FOCUSING IN THE PLAINS ALONG
TROUGH/WEAK FRONT AND TO OUR SOUTH ALONG EAST-WEST FRONT. WILL
KEEP POPS GOING FOR LATE IN THE DAY ON THU...THEN BLANKET POPS THROUGH
SAT IN A MORE TYPICAL SUMMERLIKE REGIME WITH EAST-WEST FRONT IN
VICINITY. THE PATTERN SUGGESTS STRONG CONVECTION AND LOCALLY EXCESSIVE RAINS 
LIKELY ALONG THE FRONTAL ZONE.  

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

$$

05