Flash Flood Warning 8, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
330 AM CDT TUE JUL 20 1999

WATER VAPOR LOOP SHOWING JET STREAM CONTINUING FROM THE EASTERN
PACIFIC UP THROUGH THE NORTHLAND AND INTO THE LAKE STATES OVER MEAN
RIDGE CENTERED ACROSS SOUTHERN ILLINOIS.  SHORTWAVE MOVING THROUGH
THE FLOW AND AT 06Z WAS LOCATED NEAR THE VICINITY OF EASTERN
WYOMING.  SURFACE FRONTAL BOUNDARY REMAINS QUASI-STATIONARY
ACROSS SOUTHERN NEBRASKA/SOUTHERN IOWA/CENTRAL ILLINOIS.  MAIN
CHALLENGE THIS FORECAST PACKAGE WILL BE TO RESOLVE PRECIPITATION
TIMING AND FLOODING POSSIBILITIES.

20/00Z MODEL INITIALIZATION NOT TO DIFFERENT BUT BY THE T+6 FORECAST
THEY HAVE TIMING DIFFERENCES ALREADY.  THIS PROBLEM CONTINUES
THROUGH THE FORECAST PERIOD REGARDING THE INCOMING SYSTEM.

CONVECTIVE ACTIVITY ALONG THE WARM FRONT TO THE SOUTH CONTINUES
MOVING TO THE EAST-NORTHEAST AT 25 KNOTS.  CLOUD TOP TEMPERATURES
ASSOCIATED WITH THIS COMPLEX OF STORMS CONTINUES TO WARM.  TIMING OF
THIS ACTIVITY WOULD BRING IT INTO SOUTHEAST MINNESOTA DURING THE
MORNING HOURS... SHOULD IT PERSIST.  ASSOCIATED CLOUDINESS WILL
OVERSPREAD THE FORECAST AREA THIS MORNING WHICH SHOULD PROHIBIT
SIGNIFICANT TEMPERATURE RISES.  WILL DROP AFTERNOON HIGHS A CATEGORY
AS A RESULT

AFOREMENTIONED SHORTWAVE MOVES INTO THE UPPER MISSISSIPPI RIVER
VALLEY REGION TODAY.  AN ABUNDANCE OF MOISTURE ASSOCIATED WITH
TROPICAL CONNECTION IS BEING TRANSPORTED INTO THE REGION... RESULTING
IN PRECIPITABLE WATERS IN EXCESS OF 2 INCHES.  NEEDLESS TO SAY... THIS IS
WELL ABOVE NORMAL.  AS THE WARM FRONT TO OUR SOUTH MOVES NORTH
TODAY THIS MOISTURE WILL COMBINE WITH WARM ADVECTION AT 850...
ISENTROPIC LIFT... ALREADY SATURATED SOILS... AND JET DYNAMICS TO
PRODUCE A SCENARIO PRIMED FOR FLOODING RAINS.  EXPECT ACTIVITY TO
MOVE INTO NORTHEAST IOWA/SOUTHEAST MINNESOTA THIS MORNING... INTO
WISCONSIN EARLY AFTERNOON AND CENTRAL WISCONSIN COUNTIES THIS
EVENING.  THIS ACTIVITY SHOULD CONTINUE INTO THE TONIGHT PERIOD
ESPECIALLY WITH CLIMATOLOGY OF HEAVY RAINFALL IN MIND.  THEREFORE...
WILL ISSUE A FLASH FLOOD WATCH FOR ALL OF THE FORECAST AREA WITH THE
EXCEPTION OF CLARK/TAYLOR/ADAMS/JUNEAU COUNTIES BASED ON TIMING
CONSIDERATIONS TODAY.  WILL CONTINUE FOR ALL ZONES TONIGHT WHICH
THIS WILL INCLUDE COUNTIES LEFT OUT FOR THE TODAY PERIOD.  NOTE THAT
MANOUSOS QPF WIDGET INDICATES POINT MAXIMUM OF 7 INCHES THROUGH THE
EVENT POSSIBLE.

COORDINATED WITH DVN/DMX/MPX/MKX/GRB.

.LSE...FLASH FLOOD WATCH...TODAY AND TONIGHT...MNZ086-087-094-095-
IAZ008>010-018-019-029.
FLASH FLOOD WATCH...THIS AFTERNOON AND TONIGHT...MNZ079-088-096-IAZ011-
030-WIZ032>034-041-042-053.
FLASH FLOOD WATCH...TONIGHT...WIZ017-029-043-044.

KRC

IAC005-037-043-065-067-089-131-199-MNC039-045-055-099-109-157-169-
WIC001-011-019-023-043-053-057-063-081-103-119-121-123-200200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
518 AM CDT TUE JUL 20 1999

...HEAVY RAINS LIKELY WITH FLOODING POSSIBLE THIS AFTERNOON AND
TONIGHT...ALONG WITH A SLIGHT RISK OF SEVERE THUNDERSTORMS...

SHOWERS AND THUNDERSTORMS...WITH LOCALLY HEAVY RAINFALL...WILL MOVE
INTO SOUTHEAST MINNESOTA...NORTHEAST IOWA AND SOUTHWEST WISCONSIN BY
THIS AFTERNOON AND CONTINUE THROUGH LATE TONIGHT. FLOODING IS A
SIGNIFICANT THREAT THROUGH LATE TONIGHT...AS MANY AREA CREEKS AND
RIVERS ARE ALREADY RUNNING HIGH DUE TO RECENT HEAVY RAINFALL.
THEREFORE...FLASH FLOOD WATCHES HAVE BEEN POSTED FOR THE ENTIRE AREA
FOR TODAY AND TONIGHT.

IN ADDITION TO THE FLOODING POTENTIAL...THE STORM PREDICTION CENTER
IN NORMAN OKLAHOMA HAS FORECAST A SLIGHT RISK OF SEVERE
THUNDERSTORMS THIS AFTERNOON AND TONIGHT OVER NORTHEAST
IOWA...SOUTHWEST MINNESOTA AND MUCH OF SOUTHWEST WISCONSIN. WHILE
THE INGREDIENTS DO NOT APPEAR TO BE SUFFICIENT TO PRODUCE LARGE
HAIL...WEAK TO MODERATE WIND SHEAR MAY PROMOTE THE ORGANIZATION OF
LONGER-LIVED STORMS WHICH COULD PRODUCE STRONG AND GUSTY
WINDS...PERHAPS EXCEEDING SEVERE LIMITS.

STORM SPOTTER ACTIVATION MAY BE REQUIRED FROM THIS AFTERNOON THROUGH
THE LATE EVENING HOURS.

IAC005-037-043-065-067-089-131-199-MNC039-045-055-099-109-157-169-
WIC001-011-019-023-043-053-057-063-081-103-119-121-123-200200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
518 AM CDT TUE JUL 20 1999

...HEAVY RAINS LIKELY WITH FLOODING POSSIBLE THIS AFTERNOON AND
TONIGHT...ALONG WITH A SLIGHT RISK OF SEVERE THUNDERSTORMS...

SHOWERS AND THUNDERSTORMS...WITH LOCALLY HEAVY RAINFALL...WILL MOVE
INTO SOUTHEAST MINNESOTA...NORTHEAST IOWA AND SOUTHWEST WISCONSIN BY
THIS AFTERNOON AND CONTINUE THROUGH LATE TONIGHT. FLOODING IS A
SIGNIFICANT THREAT THROUGH LATE TONIGHT...AS MANY AREA CREEKS AND
RIVERS ARE ALREADY RUNNING HIGH DUE TO RECENT HEAVY RAINFALL.
THEREFORE...FLASH FLOOD WATCHES HAVE BEEN POSTED FOR THE ENTIRE AREA
FOR TODAY AND TONIGHT.

IN ADDITION TO THE FLOODING POTENTIAL...THE STORM PREDICTION CENTER
IN NORMAN OKLAHOMA HAS FORECAST A SLIGHT RISK OF SEVERE
THUNDERSTORMS THIS AFTERNOON AND TONIGHT OVER NORTHEAST
IOWA...SOUTHWEST MINNESOTA AND MUCH OF SOUTHWEST WISCONSIN. WHILE
THE INGREDIENTS DO NOT APPEAR TO BE SUFFICIENT TO PRODUCE LARGE
HAIL...WEAK TO MODERATE WIND SHEAR MAY PROMOTE THE ORGANIZATION OF
LONGER-LIVED STORMS WHICH COULD PRODUCE STRONG AND GUSTY
WINDS...PERHAPS EXCEEDING SEVERE LIMITS.

STORM SPOTTER ACTIVATION MAY BE REQUIRED FROM THIS AFTERNOON THROUGH
THE LATE EVENING HOURS.