Severe Thunderstorm Warning 68, NWS Green Bay, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
315 PM CDT SUN JUL 25 1999

TSTM CHCS ARE THE MAIN CONCERN TONIGHT INTO MONDAY.

A WEAK RIDGE OF HIGH PRESSURE AND ITS ASSOCIATED DRIER AIR WAS SITUATED
OVER MUCH OF NE WI EARLY THIS AFTERNOON. A COLD FRONT EXTENDED FROM
EXTREME NW MN SWWD INTO WSTRN NEB SD...WITH A WARM FRONT EXTENDING FROM
NC MN INTO PARTS OF FAR WC AND SW WI. IN THE WARM SECTOR...A TROPICAL
FEED OF MOISTURE HAD RAISED DEWPOINTS INTO THE MIDDLE TO UPPER 70S. AN
IMPRESSIVE LINE OF TSTMS HAD DEVELOPED IN ADVANCE OF THE COLD FRONT OVER
NW MN AND FAR SE ND...WHERE CAPES WERE AS HIGH AS 5000 J/KG. ANOTHER
FEATURE OF NOTE WAS THE S/W TROF OVER EASTERN NEB...WHICH WAS MOVG
STEADILY TO THE NE.

MODELS ARE IN GENERAL AGREEMENT ON MOVG THE COLD FRONT INTO THE FAR NW
PORTION OF GRB CWA BY 12Z/MON...THEN SHIFTING IT OUT OF EC WI BY EARLY
TO MID-AFTERNOON. ETA IS A FEW HOURS SLOWER...AND WILL FOLLOW.
INCREASING MOISTURE AND INSTABILITY IN ADVANCE OF THE FRONT...PLUS SOME
S/W ENERGY AND A WEAKENING CAP SHOULD SUPPORT SCT TSTM DEVELOPMENT
OVERNIGHT. ACTIVITY SHOULD END WITH THE PASSAGE OF THE FRONT...AS
EVIDENCED BY A LACK OF POST-FRONTAL SHOWERS/CLOUDS ACROSS THE NORTHERN
PLAINS. TWO SMALL WINDOWS OF OPPORTUNITY EXIST FOR SVR IN GRB CWA. PRE-
FRONTAL SQUALL LINE SHOULD CONTINUE TO SHIFT EAST THIS EVG...REACHING
PARTS OF NC/C WI BEFORE MIDNIGHT. ALTHOUGH THIS LINE WILL BE WEAKENING
AS IT SHIFTS EAST...SOME ISOLD SVR STORMS WITH DAMAGING WINDS ARE
POSSIBLE. ALSO...IF THE ETA VERIFIES WITH THE SLOWER MOVMT OF THE
FRONT...INSTABILITY MAY INCREASE ENOUGH ACROSS PARTS OF NE/EC WI EARLY
MONDAY AFTERNOON TO PROVIDE ANOTHER CHC. NOT CONFIDENT ENOUGH IN EITFHER
SCENARIO TO MENTION IN THE ZONES.

MOS GUIDANCE SEEMS OK...BUT PERHAPS A BIT ON THE WARM SIDE FOR MONDAY
AND MONDAY NIGHT.

.GRB...NONE.

KIECKBUSCH
WWW.CRH.NOAA.GOV/GRB