[LeArc] Forecast Discussion : MLI@ 8/12/2003 2:27:55 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 121925
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
225 PM CDT TUE AUG 12 2003


UPPER AIR FEATURES INCLUDE A RIDGE EXTENDING NORTHEAST TO SOUTHWEST 
ACROSS OUR AREA AT 850 AND 700 MB...WITH THE RIDGE FURTHER WEST AT 
500 MB AND 250 MB. THE RIDGE IS OVER THE WEST AT 250 MB...WITH A 
TROF TO THE WEST OF IT OVER THE EASTERN PACIFIC OCEAN. VERY LITTLE 
JET ENERGY OVER OUR AREA...BUT THERE IS A LOT OF JET ENERGY ON THE 
NORTHWEST SIDE OF THE RIDGE ACROSS SOUTHERN CANADA.

SURFACE FEATURES INCLUDE HIGH PRESSURE OVER NORTHERN WISCONSIN WITH 
NORTHEASTERLY FLOW AFFECTING THE ENTIRE CWA. NORTHEASTERLY FLOW 
BROUGHT IN AN OVERCAST LAYER LAKE MICHIGAN-INDUCED STRATUS EARLIER 
TODAY...WHICH HAS PRETTY MUCH BURNED OFF. DAYTIME CU HAS DEVELOPED 
THOUGH...AND THE NET CHANGE ON CLOUD COVER ACROSS OUR AREA HAS BEEN 
PRETTY MUCH ZERO (THAT IS...MOSTLY CLOUDY TO CLOUDY). SATELLITE 
SHOWS THE GREATEST VERTICAL DEVELOPMENT TO THE CLOUDS TO BE 
SOUTHEAST OF OUR CWA OVER LINCOLN/S CWA...BUT SOME HEALTHY VERTICAL 
DEVELOPMENT WAS INDICATED OVER OUR CWA TOO. RADAR SHOWS THE MOST 
INTENSE AND GREATEST COVERAGE RETURNS TO BE SOUTHEAST OF OUR 
CWA...WITH OTHER RETURNS OVER OUR CWA.

CLOUDS DISSIPATE TOWARD SUNSET TODAY AS WE LOSE DAYTIME HEATING. 
EXPECT CLEAR SKIES TONIGHT...BUT A LAKE MICHIGAN-INDUCED STRATUS 
LAYER IS ALSO POSSIBLE TONIGHT GIVEN NORTHEASTERLY WINDS. CLOUDS 
REMAIN IN PLACE TOMORROW AS AIR MASS CHANGES ONLY SLIGHTLY. HAVE 
GONE UNDER GUIDANCE FOR HIGH TEMPS TOMORROW GIVEN AMOUNT OF CLOUD 
COVER WE EXPECT. EXPECT CLOUDS TO MOVE OUT FOR WEDNESDAY NIGHT AND 
HAVE MOSTLY CLEAR CONDITIONS. ...JAZ

LONGER TERM...(THURSDAY THROUGH TUESDAY)
SURFACE HIGH PRESSURE WILL GRADUALLY SHIFT EAST AND SOUTH 
THURSDAY...BRINGING WINDS AROUND TO THE SOUTH AND ALLOWING FOR 
WARMER TEMPERATURES.  MODELS CONTINUE TO INDICATE SOME INSTABILITY 
DURING THE AFTERNOON WITH WEAK FORCING.  INHERITED 20 POPS FOR THE 
SOUTHEAST HALF OF THE AREA FROM PREVIOUS ISSUANCE...AND SEE LITTLE 
REASON TO CHANGE THIS.  AFTER THIS...UPPER RIDGING DOMINATES THE 
MIDWEST THROUGH LATE IN THE WEEKEND.  TEMPERATURES WILL LIKELY RISE 
ABOVE SEASONAL NORMS WITH RELATIVELY DRY AIRMASS AND SOUTHERLY FLOW 
AT LOW LEVELS. BY SATURDAY NIGHT...A POTENT SHORT WAVE TROF WILL 
OVERTOP THE UPPER RIDGE IN SOUTHERN CANADA.  THIS WILL HELP DRIVE A 
FRONT SOUTH TO NORTHERN IOWA BY SUNDAY MORNING. THE AREA WILL BE ON 
THE SOUTHERN EDGE OF THE STRONGER WESTERLY FLOW ALOFT SUNDAY AND 
MONDAY AND WITH THE FRONT IN THE AREA WILL INCLUDE A 30 POP FOR 
TSRA. WARM CONDITIONS WILL CONTINUE INTO TUESDAY AS SOUTHWEST FLOW 
CONTINUES IN ADVANCE OF THE APPROACHING UPPER TROF.  HAVE INTRODUCED 
SLIGHT CHANCE POPS TUESDAY TO COVER SOME ENERGY SPREADING INTO THE 
AREA PER THE 12Z GFS SOLUTION.  

ERVIN

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

$$