[LeArc] Forecast Discussion : MLI@ 6/7/02 2:17:26 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 070712
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
211 AM CDT FRI JUN 7 2002

MSAS AND SURFACE ANALYSIS SHOW PERSISTENT SOUTHERLY FLOW ACROSS
MISSOURI RIVER VALLEY IS PROGRESSING EASTWARD AS HIGH PRESSURE SYSTEM
SLIDES EAST ACROSS MICHIGAN.  BEST SPEED CONVERGENCE APPEARS TO BE IN
SOUTHERN MINNESOTA. 850 MB PROFILER DATA ALSO INDICATING BEST LOW LEVEL
JET FEEDING UP THE MISSOURI RIVER VALLEY.  RADAR SUPPORTS THIS WITH
CONTINUED SHOWER AND THUNDERSTORM ACTIVITY JUST NORTH OF THE IOWA BORDER
WHILE ACTIVITY IN EAST NEBRASKA IS DIMINISHING.  300 MB JET STREAK
ACROSS MONTANA INTO NORTH DAKOTA PROVIDING ENOUGH DYNAMIC LIFT FOR A FEW
SHOWERS IN THAT REGION.

FORECAST CHALLENGES TODAY WILL BE FORECASTING AMOUNT OF CLOUD
COVER...ESPECIALLY ACROSS NORTHERN SECTION OF FORECAST AREA...
ALONG THE HIGHWAY 20 REGION.  THAT SAME REGION WILL ALSO NEED TO
BE LOOKED AT FOR SHOWERS POSSIBLE BY TONIGHT DEPENDING ON THE
POSITIONING OF THE FRONT APPROACHING OUT OF THE DAKOTAS.  AT THIS
TIME...MODELS STILL KEEPING THIS FRONT JUST NORTH OF THE IOWA
BORDER THROUGH SATURDAY MORNING.  SPC EVEN OUTLOOKED OUR
FORECAST AREA IN SLIGHT RISK.  BUT WITH VERY WET GROUND...AFTERNOON HIGH
TEMPERATURES MAY STRUGGLE AGAIN TODAY AND BETTER SURFACE DEW POINTS
APPEAR TO BE HOLDING SOUTH.  WILL ADD SOME 20 OR 30 POPS TO FAR NORTH
IOWA COUNTIES ONLY.  IN THE EXTENDED...AS USUAL...SOME DIFFERENCES IN
TIMING OF FRONTAL PASSAGE BUT MIKE DID A NICE JOB WITH THIS IN PREVIOUS
PACKAGE EXPLAINING DIFFICULTIES OF FRONTS PUSHING AS FAR SOUTH AS MODELS
INDICATE THIS TIME OF YEAR IN A STRONG SOUTHERLY FLOW.

ETA PLACEMENT OF A WEAK SHORTWAVE ACROSS NORTHERN IOWA SEEMS TO BE A
LITTLE FAST.  BETTER SHORT WAVE FORECAST ACROSS NORTHWEST IOWA
SATURDAY MORNING.  AVN HINTING AT SOMEWHAT THE SAME THING.  BOTH ETA
AND AVN...USING CONCEPTUAL MODEL...KEEP BEST SURFACE AND 500 MB
CONVERGENCE TO THE WEST AND NORTH OF OUR FORECAST.  A LOT IN OUR AREA
WILL DEPEND ON OUTFLOW BOUNDARIES AND DEBRIS FROM WHAT HAPPENS OUTSIDE
OF OUR FORECAST AREA.

AFTER COORDINATION WITH DES MOINES...WILL KEEP DRY FORECAST GOING TODAY
AND TONIGHT FOR ALL OF FORECAST AREA EXCEPT FOR BUCHANAN...DELAWARE AND
DUBUQUE COUNTIES...ADDING SOME 30 POPS TO THOSE COUNTIES...BUT JUST DO
NOT THINK THE FRONT WILL BE ABLE TO DROP ANY FARTHER SOUTH TODAY.  WILL
UP SOUTH WINDS A NOTCH OR TWO ACROSS ENTIRE FORECAST AREA TODAY.  OLD
PACKAGE OF 10 TO 15 WILL PROBABLY BE MORE ALONG THE LINES OF 15 TO 20.
GROUND STILL PRETTY WET WHICH MAY MAKE IT HARD FOR MAX TEMPERATURES TO
HIT 80...BUT WITH STRONG SOUTHERLY FLOW WILL COUNTER THIS ENOUGH TO
LEAVE CURRENT WORDING AS IS.

MIKE DID A NICE JOB WITH EXTENDED AND SEE NO REASON TO CHANCE
ANYTHING AT THIS TIME.

THANKS DES MOINES FOR THE COORDINATION.

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

MEYER