Severe Thunderstorm Warning 96, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
345 AM CDT THU JUL 18 2002

DATA ANALYSIS AT 18/06Z SHOWS THE FRONT EXTENDING FROM JUST NORTH OF
A KAUW-KULM-KMML LINE.  REGIONAL RADAR SHOWING SCATTERED SLOW MOVING
THUNDERSTORMS OVER EASTERN IOWA WHERE THE CAP IS THE WEAKEST.  LOW
LEVEL MOISTURE TRANSPORT HAS LEAD TO THE DEVELOPMENT OF AN MCS OVER
NORTH DAKOTAS.  AIRMASS OVER THE FORECAST AREA REMAINS CAPPED FOR
NOW.  MAIN FORECAST FOCUS WILL BE THE FRONT MOVING INTO...THEN
THROUGH THE FORECAST AREA TODAY AND TONIGHT.

MODEL INITIALIZATION OF THE ETA/AVN SEEMS REASONABLE.  ETA IS MUCH
FASTER BRINGING THE FRONT THROUGH THE FORECAST AREA THAN THE AVN.
IN FACT...THE ETA CAPE/LI FIELDS SUGGEST TIMING SIMILAR TO THE AVN.
THINK THE FRONT WILL PUSH INTO THE CENTRAL PORTION OF THE FORECAST
AREA /KLSE-KRST-KVOK/ ABOUT 17Z...THEN THROUGH THE FORECAST AREA BY
00Z.

MUCAPES WILL BUILD AHEAD OF THE FRONT TO ABOUT 2500 J/KG BY
MIDDAY...AND 3500 J/KG BY PEAK HEATING.  THIS IN CONJUNCTION WITH A
WEAK CAP /0-30 CIN NEAR THE FRONT/ AND CONVERGENCE ALONG THE FRONT
SHOULD CAUSE THE BOUNDARY TO CONVECT THIS MORNING AS IT MOVES
SOUTH.  THIS SHOULD CONTINUE TODAY INTO THE EVENING AS IT HEADS
SOUTH.  ABOVE AVERAGE CONFIDENCE FOR THIS GIVEN WHAT HAPPENED TODAY
ACROSS MINNESOTA AND NORTHERN WISCONSIN NEAR THIS FRONT.

SEVERE THREAT WITH THESE STORMS SHOULD BE MAINLY HAIL GIVEN THE
AMOUNT OF INSTABILITY /SEE CAPE ABOVE/ AND WET BULB ZERO HEIGHTS OF
11-12 KFT.  HOWEVER...ENVIRONMENTAL SHEAR REMAINS WEAK WITH THESE
STORMS.  THEREFORE...DO NOT EXPECT ANY LONG LIVED ROTATING UPDRAFTS
OR ORGANIZED LINEAR SEGMENTS.

LOOK AT THE 18/06Z ETA SUGGESTS THE PRECIPITATION ONSET WILL BE
DELAYED A FEW HOURS.  THEN...IT DEVELOPS SOME ADDITIONAL MOISTURE
TRANSPORT TONIGHT...WHICH ENHANCES CONVECTION INTO AN MCS.  THIS
SEEMS REASONABLE...AND GIVEN CURRENT FORECAST...WILL CONTINUE CHANCE
OF THUNDERSTORMS TONIGHT.

HIGH PRESSURE BUILDS INTO THE GREAT LAKE STATES FRIDAY THROUGH
SATURDAY.  THIS WILL PRODUCE EASTERLY FLOW ACROSS THE FORECAST AREA.
THIS WILL KEEP HIGHS DOWN SOME...DESPITE WARM 850 MB TEMPERATURES
CONTINUING.  PRECIPITATION CHANCES NIL WITH A DRY BOUNDARY
LAYER...AND NOT TOO MANY CLOUDS FOR FRIDAY AND SATURDAY.

.LSE...NONE.

KRC

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-190300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
1240 PM CDT THU JUL 18 2002

HAZARD - SLIGHT RISK OF SEVERE THUNDERSTORMS...WITH THE PRIMARY
THREAT BEING LARGE HAIL AND DAMAGING WINDS.

TIMING - FOR THIS AFTERNOON THROUGH THIS EVENING.

LOCATION - SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST
WISCONSIN.

DISCUSSION - A NEARLY STATIONARY FRONT EXTENDED FROM EASTERN
WISCONSIN INTO SOUTHERN MINNESOTA. THIS FRONT WILL CONTINUE TO MOVE
SLOWLY SOUTH THIS AFTERNOON...AND WILL SERVE AS A FOCAL POINT FOR
SHOWERS AND THUNDERSTORMS. THE ATMOSPHERE AROUND THE AREA IS MOIST
AND UNSTABLE...AND A FEW OF THESE STORMS WILL HAVE THE POTENTIAL TO
PRODUCE LARGE HAIL AND DAMAGING WINDS. LOCALLY HEAVY RAINFALL IS
ALSO A POSSIBILITY...DUE TO THE SLOW MOVEMENT OF THE STORMS.

SPOTTER INFORMATION - SPOTTER ACTIVATION MAY BE NEEDED.

THOMPSON