[LeArc] Forecast Discussion : MLI@ 6/17/02 2:14:30 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 171915
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
214 PM CDT MON JUN 17 2002

NORTHWEST FLOW CONTINUES WITH THE NEVER ENDING STREAM OF SHORTWAVES
COMING DOWN THE PIKE.  CURRENT WAVE MOVING ACROSS NORTHWEST AND
CENTRAL IOWA AT THIS TIME WITH NEXT WAVE IN MONTANA AND THE WEST
DAKOTAS ON ITS HEALS.  LATEST ANALYSIS AND MSAS DATA INDICATING DEW
POINTS STILL FAIRLY DRY ACROSS DVN FORECAST AREA.  HIGHER 60 DEW
POINT AIR NUDGING INTO KANSAS INTO SAME AREA WHERE 3 HOUR PRESSURE
FALLS ARE BEST.

AT THE RISK OF SOUNDING LIKE A BROKEN RECORD...MORE OF THE SAME FOR
AT LEAST ONE MORE DAY WITH PRIMARY FORECAST CHALLENGE BEING
TIMING OF WAVES AND ASSOCIATED SHOWERS...THUNDERSTORMS AND QPF.  WITH
A SOMEWHAT BROAD UPPER RIDGE FORECAST TO BUILD ACROSS THE CENTRAL
U.S. WITH WARM AND MOIST AIR MAKING A RETURN TO THE MIDWEST...TIMING
OF SHOWERS AND THUNDERSTORMS THROUGHOUT THE ENTIRE 7 DAY PACKAGE WILL
REQUIRE A CLOSE EYE.

ETA AND AVN INITIALIZED WELL WITH CURRENT PLACEMENT OF MONTANA
WAVE...BUT AT 18Z...AVN DROPPED IT WHILE ETA BRINGS IT DOWN THE
NORTHWEST FLOW.  ETA PLACED THE 12Z PRECIPITATION FAIRLY CLOSE OVER
NORTHWEST IOWA AND SOUTHEAST SOUTH DAKOTA AND MESOETA WAS A LITTLE
BETTER YET.  THE MEDIUM RANGE GUIDANCE STILL SHOWS SOMEWHAT BIG
CHANGES TO THE LARGE SCALE FLOW.  THE CURRENT HIGHLY AMPLIFIED FLOW
ACROSS THE CENTRAL U.S. IS STILL FORECAST TO DEAMPLIFY.  THIS SHOULD
RESULT IN A MORE SUMMER LIKE PATTERN AS UPPER HEIGHTS BUILD ACROSS
THE MIDWEST. IN THE EXTENDED...THE ECMWF STILL TRYING TO PLACE
SURFACE FRONTAL BOUNDARY A LITTLE FURTHER SOUTH COMPARED TO THE MRF.

LOOKING AT THE SHORT RANGE AND MEDIUM FORECAST...WILL LEAVE A CHANCE
OF SHOWERS AND THUNDERSTORMS IN NORTH ZONES AND WEST ZONES BUT GO
WITH ONLY SLIGHT CHANCE FOR SOUTH ZONES AND EAST ZONES.  LAPSE RATES
STILL ARE NOT VERY IMPRESSIVE ACROSS OUR FORECAST AREA OVERNIGHT...
LOOKING BETTER FOR THUNDERSTORMS OVER WEST IOWA INTO NEBRASKA...SO
WILL GO WITH SOME ISOLATED THUNDER WORDING.  WILL BUMP LOWS DOWN A
NOTCH USING CURRENT DEW POINTS AS GUIDANCE.  ANOTHER BIG QUESTION
MARK IS IF COMPLEX DOES DEVELOP OVERNIGHT IN SOUTHEAST NEBRASKA
AREA...WHICH MESOETA HINTS AT...WOULD EVEN FURTHER HINDER LOW LEVEL
MOISTURE FEED TO OUR FORECAST AREA. PATTERN WILL REMAIN ACTIVE ENOUGH
FOR CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH TUESDAY AND
WEDNESDAY AS IS GOING IN CURRENT PACKAGE...WITH BETTER CHANCE ON
TUESDAY.

LOOKING AT THE EXTENDED...AVN PLACES SURFACE HIGH PRESSURE OVER
WISCONSIN AND UPPER GREAT LAKES FRIDAY PULLING NORTHEAST FLOW TOWARD
OUR FORECAST AREA.  THIS MAY ENHANCE A SURFACE BOUNDARY ACROSS
SOUTHERN IOWA...BUT MODELS PLACING US UNDER A BROAD UPPER RIDGE
WITH LITTLE SUPPORT.  WILL LEAVE FRIDAY ALONE FOR NOW BUT MAY HAVE TO
BE CHANGED LATER.  THE WEEKEND LOOKS HOT AND STORMY WITH A SATURDAY
NIGHT SUNDAY TIME FRAME LOOKING BEST.  WILL BRING MONDAY...DAY 7...IN
FREE OF RAIN AND THUNDER.

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

MEYER