Friday, March 21, 2008

latest discussion

Latest Satellite Discussion

EVENT...BAND OF MODERATE TO HEAVY SNOW BEGINNING TO INCREASE ACROSS S
WI/FAR N IL/SW MI.
.
SATELLITE ANALYSIS AND TRENDS...SATELLITE DATA SHOWS THAT THE EVOLUTION
OF THE HEAVY SNOW EVENT APPEARS TO BE FOLLOWING ALONG RATHER CLOSELY
WITH EARLIER HPC WWD GRAPHIC -(MAYBE JUST A HAIR TO THE NORTH) AND SPC
MESOSCALE DISCUSSION. LATEST VISIBLE IMAGERY SHOWS BEST TEXTURED CLOUD
ELEMENTS LINING UP WELL WITH METAR SNOW OBSERVATIONS AND RADAR COMPOSITE
REFLECTIVITIES FROM S CENT AND SE MN TO SW MI. RECENT TRENDS IN WATER
VAPOR IMAGERY INDICATE A SIGNIFICANT IMPULSE/MID-UPPER LEVEL SPEED MAX
HAS MOVED NORTHEASTWARD FROM THE CENTRAL PLAINS INTO THE DISCUSSION AREA
WHICH SEEMS TO HAVE STRENGTHENED 850-500MB FRONTOGENETIC FORCING AND
ENHANCED CLOUD TOPS AND RADAR RETURNS OVER N IL/S CENT AND SE WI. IN
RESPONSE AN INCREASE IN SNOW INTENSITY HAS BEEN REPORTED AT STATIONS
SUCH AS MADISON(KMSN) AND MILWAUKEE(KMKE) IN SOUTHERN AND SERN WISCONSIN
WITH AT LEAST 1"/HR NOTED, AND CHICAGO-WAUKEGAN(KUGN) IN NORTHEASTERN
ILLINOIS. BELIEVE THIS REGION OF S CENT AND SE WI/FAR N AND NE IL
(LIKELY MORE ON THE NORTH SIDE OF CHICAGO)/SW MI WILL CONTINUE TO SEE
THE HEAVIEST SNOWS DURING THE LATE MORNING AND WELL INTO THE AFTERNOON
WITH 1"/HR RATES COMMON AND THE LIKELIHOOD OF RATES EVEN APPROACHING
2"/HR PARTICULARLY IN THE USUAL BANDING FEATURES AND ALSO IN LOCALIZED
SPOTS OF SE WI AND EXTREME NE IL WEST OF LAKE MICHIGAN WHERE EASTERLY
SFC FLOW OFF THE LAKE SHOULD AID IN LOCALIZED SNOWFALL EFFICIENCY. WATER
VAPOR IMAGERY AND VISIBLE LOOP BOTH POINT TOWARD A VERY SHARP SOUTHERN
CUTOFF TO THE AXIS OF HEAVIEST SNOW ACROSS THE DISCUSSION AREA AS DRY
SLOT PUSHES EAST ACROSS IOWA AND BREAKS IN CLOUDS NOTED ACROSS S CENT AND
E IA AND ALSO JUST SOUTH OF CHICAGO. THE APPROACH OF THE DRY SLOT COULD
FURTHER DESTABILIZE THE SITUATION WITH CONVECTIVE TYPE CELLS POTENTIALLY
DEVELOPING ON THE NORTHEAST FRINGE OF IT WHICH AGAIN POINTS TO S CENT
AND SE WI/FAR N AND NE IL/SW MI. A GRAPHICAL DEPICTION OF SATELLITE
FEATURES SHOULD BE AVAILABLE ON THE INTERNET ADDRESS LISTED BELOW IN
APPROXIMATELY 10 MINUTES.

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