Damaging Wind in Wisconsin, April 17, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
310 PM CDT FRI APR 16 2004

.DISCUSSION...FORECAST FOCUS IS ON THUNDERSTORM CHANCES AND
TEMPERATURES THIS WEEKEND.

ACTIVE WEATHER ON TAP FOR THIS WEEKEND. 25KT LOW LEVEL JET NOSE
POINTING TO SOUTHERN MINNESOTA AT THIS TIME HELPING TO GENERATE
CONVECTION. THIS FEATURE SHOULD SHIFT ACROSS SOUTHERN AND CENTRAL
WISCONSIN TONIGHT...AND INCREASE IN MAGNITUDE TO AROUND 40KT. THIS
SHOULD COMBINE WITH ELEVATED CAPES OF 500-1000 J/KG...SOME MID
LEVEL MOISTURE...AND AN ADVANCING SURFACE COLD FRONT...TO BRING A
CHANCE OF THUNDERSTORMS LATER THIS EVENING AND OVERNIGHT. COULD SEE
A SMALL MCS DEVELOP WITH THE DECENT LIFT ASSOCIATED WITH THE LOW
LEVEL JET...BUT RELATIVELY DRY LOW LEVELS SHOULD KEEP CONVECTION
ELEVATED IN NATURE. SURFACE AIR PARCEL TRAJECTORIES BRING AIRMASS
FROM CENTRAL MISSOURI INTO CWA TONIGHT...WHERE LOWS THIS MORNING
WERE IN LOW TO MID 50S F. THESE SEEM REASONABLE TO USE FOR TONIGHT.

THE PRECIPITATION SHOULD END SATURDAY MORNING...AS THE LOW LEVEL JET
WEAKENS AND SHIFTS EASTWARD. A TRICKY HIGH TEMPERATURE FORECAST FOR
SATURDAY...AS SURFACE COLD FRONT/PNEUMONIA-TYPE FRONT PROPAGATE
THROUGH THE CWA. MODELS HAVE THIS FEATURE ALMOST TO THE
WISCONSIN/ILLINOIS BORDER AT 18Z SATURDAY...WITH A QUICK WIND SHIFT
TO THE NORTHEAST IN ITS WAKE. FORECAST SOUNDINGS INDICATE 25KT WINDS
MIXING DOWN TO THE SURFACE DURING THE AFTERNOON. THE SOUNDINGS ALSO
SHOW A LOW STRATUS DECK ADVECTING INTO THE LAKESHORE AREAS...AND
SPREADING INLAND DURING THIS TIME. LAKE MICHIGAN MID-LAKE
TEMPERATURES ARE STILL IN THE UPPER 30S F...AND THIS WOULD OBVIOUSLY
HELP COOL TEMPERATURES DOWN...ESPECIALLY NEAR THE LAKE. WILL GO WITH
LOW TO MID 60S F FOR HIGHS NEAR LAKE AROUND NOON...THEN DROP THEM
INTO THE 40S F BY LATE AFTERNOON. THE SOUTHWEST CWA SHOULD BE THE
WARMEST...WITH A COOL-DOWN FROM EAST TO WEST DURING THE AFTERNOON.

CHANCES FOR THUNDERSTORMS INCREASE FOR SATURDAY NIGHT...AS THE
PREVIOUSLY-MENTIONED COLD FRONT RETURNS NORTH ACROSS THE CWA AS A
WARM FRONT. AGAIN...40KT+ LOW LEVEL JET NOSE EXPECTED TO INITIATE
CONVECTION ACROSS IOWA AROUND BY 00Z SUNDAY...AND THEN POINT TOWARDS
THE CWA AND INCREASE IN MAGNITUDE TO 45-50KT BY 06Z SUNDAY.
FORECAST SOUNDINGS SHOW THE EXPECTED LOW LEVEL INVERSION...WITH
QUITE AN UNSTABLE AIRMASS ABOVE THE INVERSION. LIFTING AIR PARCELS
FROM THE 850MB LEVEL YIELDS ELEVATED CAPES OF UP TO 3000 J/KG...
WITH CURVED HODOGRAPHS YIELDING VERY HIGH 0-1KM AND 0-3KM
HELICITIES...BOTH OVER 400M2/S2. WET BULB ZERO HEIGHTS REMAIN
BELOW 9000 FEET...WHICH GIVEN THE ABOVE PARAMETERS...COULD YIELD A
GOOD CHANCE FOR SEVERE HAIL. SPC HAS CWA IN SLIGHT RISK FOR DAY 2...
WHICH LOOKS GOOD. WILL GO WITH LIKELY POPS IN THE NORTHERN CWA...AS
THE LOW LEVEL JET NOSE POINTS MORE IN THAT VICINITY...AND 50 POPS
ACROSS THE SOUTH. ALL IN ALL...EXPECT AN WELL-ORGANIZED MCS TO
PROPAGATE THROUGH THE REGION OVERNIGHT.

CHANCES FOR CONVECTION ARE LESS CERTAIN FOR SUNDAY...AS THE MAIN
COLD FRONTAL BOUNDARY IS EXPECTED TO BE WELL WEST OF THE CWA. SOME
QUESTION AS TO THE AMOUNT OF LEFTOVER CLOUDS FROM DEPARTED MCS...
WHICH WOULD KEEP CWA CAPPED. THIS WOULD ALSO KEEP CWA COOLER.
HOWEVER...IF CLOUDS BREAK UP...COULD SEE SOME ISOLATED CONVECTION IF
LOW LEVEL JET NOSE HELPS TO ERODE ANY LEFTOVER CAPPING. WILL LEAVE 30
POPS FOR NOW ON SUNDAY.

BETTER CHANCE OF ORGANIZED CONVECTION SUNDAY NIGHT WITH A SURGING
COLD FRONT. COULD SEE ANOTHER ROUND OF POSSIBLY SEVERE CONVECTION
GIVEN THE STRONG DEEP-LAYER SHEAR AND MODEST ELEVATED INSTABILITY.
SPC HAS CWA IN SLIGHT RISK FOR DAY 3 AS WELL.

NEXT WEEK LOOKS MOSTLY DRY WITH SEASONABLE TEMPERATURES...IN A MORE
ZONAL FLOW PATTERN.

&&

.MKX...NONE.

WOOD

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
515 AM CDT FRI APR 16 2004

WIZ046-047-051-052-056>060-062>072-171000-
COLUMBIA-DANE-DODGE-FOND DU LAC-GREEN-GREEN LAKE-IOWA-JEFFERSON-
KENOSHA-LAFAYETTE-MARQUETTE-MILWAUKEE-OZAUKEE-RACINE-ROCK-SAUK-
SHEBOYGAN-WALWORTH-WASHINGTON-WAUKESHA-
515 AM CDT FRI APR 16 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

FIRE WEATHER CONDITIONS WILL APPROACH CRITICAL FIRE WEATHER CRITERIA
THIS AFTERNOON OVER SOUTHERN WISCONSIN. THE COMBINATION OF LOW
HUMIDITIES AND WARM TEMPERATURES DURING THE AFTERNOON HOURS WILL
INCREASE THE FIRE DANGER.

THERE WILL BE A CHANCE OF THUNDERSTORMS TONIGHT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY NIGHT.  THE
MAIN THREAT WILL BE DAMAGING WINDS AND LARGE HAIL.

THERE WILL BE A CHANCE OF THUNDERSTORMS SUNDAY AND SUNDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTER GROUPS WILL NOT BE NEEDED.

ZAJDEL