Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 281139
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
639 AM CDT THU MAY 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 328 AM CDT THU MAY 28 2015

LATEST WATER VAPOR SATELLITE IMAGERY SHOWS SHORTWAVE RIDGE EXTENDING
FROM WESTERN ILLINOIS INTO NORTHERN MINNESOTA AND SEVERAL WEAK
SHORTWAVE TROUGHS EMBEDDED IN SOUTHWESTERLY FLOW ALOFT OVER THE
NORTHERN AND HIGH PLAINS. LATEST 07Z SURFACE ANALYSIS SHOWS WEAK
SURFACE RIDGE OVER ILLINOIS AND EASTERN WISCONSIN.

DRY WEATHER CAN BE EXPECTED TODAY ACROSS THE FORECAST AREA...AS
SURFACE RIDGE WILL SLOWLY BUILD INTO MICHIGAN. WITH MOSTLY SUNNY
SKIES ACROSS THE REGION...TEMPERATURES SHOULD RISE INTO THE UPPER
70S TO MIDDLE 80S TODAY.

.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 328 AM CDT THU MAY 28 2015

MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES TONIGHT INTO FRIDAY
NIGHT. THE 28.00Z NAM/GFS/ECMWF SHOW SOME DIFFERENCES IN TIMING AND
PLACEMENT OF SURFACE FRONT AND THE FIRST IMPULSE TO IMPACT THE
FORECAST AREA TONIGHT. THE NAM MUCH FARTHER WEST AND SLOWER
PROGRESSION WITH SURFACE FRONT TONIGHT INTO FRIDAY. THIS IS EVIDENT
PER DPROG/DT...AS THE NAM HAS TRENDED SLOWER AND FARTHER WEST WITH
SURFACE FRONT THE LAST SEVERAL RUNS. THE 28.00Z GFS REMAINS THE
FASTEST AMONG THE MODELS. THE 28.00Z MODELS SUGGEST FIRST IMPULSE
TO MOVE INTO THE WESTERN FORECAST AREA AROUND 06Z FRIDAY AND THE
LATEST HI-RESOLUTION MODELS...ARW/NMM...SUGGEST SIMILAR TIMING.
DECENT MOISTURE TRANSPORT AND LIFT ASSOCIATED WITH SHORTWAVE
TROUGH WILL ALLOW FOR SHOWERS AND THUNDERSTORMS TO DEVELOP WEST
TO SOUTHWEST OF FORECAST AREA AND MOVE INTO THE WESTERN FORECAST
AREA AROUND 06Z FRIDAY. HAVE TRENDED TOWARD A SLOWER PROGRESSION
OF ONSET OF PRECIPITATION CHANCES TONIGHT.

SURFACE FRONT SLOWLY MOVES ACROSS THE FORECAST AREA FRIDAY INTO
FRIDAY NIGHT. AS MENTIONED BEFORE...THE 28.00Z GFS/NAM/ECMWF DIFFER
ON PROGRESSION OF FRONT. THIS WILL HAVE AN IMPACT ON HOW LONG
FRONTOGENETIC BAND OF PRECIPITATION STAYS OVER FORECAST AREA. DURING
THIS TIME PERIOD...TAKEN A BLEND OF THE TIMING OF THE FRONT BETWEEN
THE MODELS AND PRECIPITATION SHOULD EXIT THE SOUTHERN FORECAST
AREA BEFORE 18Z SATURDAY.

AS FAR AS SEVERE THREAT ACROSS FORECAST AREA FRIDAY...THE THREAT
REMAINS LOW...WITH BOTH THE 28.00Z GFS/NAM SHOW LESS THAN 15 KNOTS
OF 0-3KM SHEAR ACROSS THE FORECAST AREA AND LIMITED INSTABILITY.

UPPER LEVEL/SURFACE RIDGE BUILD INTO THE UPPER MIDWEST AND GREAT
LAKES REGION AND BECOMES THE DOMINANT WEATHER FEATURE SUNDAY INTO
NEXT WEEK. THIS SHOULD PROVIDE DRY WEATHER ACROSS THE FORECAST AREA.
HIGH TEMPERATURES ARE EXPECTED TO BE COOLER THAN NORMAL...THEN BEGIN
TO MODERATE MONDAY INTO TUESDAY...AS SOUTHERLY FLOW ADVECTS WARMER
AIR INTO THE FORECAST AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 639 AM CDT THU MAY 28 2015

VFR CONDITIONS ARE EXPECTED TODAY AT THE TAF SITES. IFR CONDITIONS
ARE EXPECTED LATE TONIGHT INTO FRIDAY MORNING IN SHOWERS AND
THUNDERSTORMS. A SHORTWAVE TROUGH WILL LIFT NORTH OUT OF THE
CENTRAL PLAINS SPREADING SHOWERS AND THUNDERSTORMS ACROSS THE TAF
SITES AFTER MIDNIGHT. PLAN ON IFR CONDITIONS IN THE THUNDERSTORMS.
THE SHOWERS AND STORMS WILL BE ONGOING FRIDAY MORNING AS A COLD
FRONT WORKS INTO THE REGION FROM THE NORTHERN PLAINS.

&&

.HYDROLOGY...
ISSUED AT 310 AM CDT THU MAY 28 2015

DUE TO RECENT RAINFALL A FEW RIVERS HAVE HAD SOME WITHIN BANK
RISES ACROSS WESTERN PART OF THE FORECAST AREA. WITH A COLD FRONT
SLOWLY MOVING ACROSS THE AREA TONIGHT INTO FRIDAY NIGHT...SHOWERS
AND THUNDERSTORMS ARE EXPECTED OVER MUCH OF THE FORECAST AREA. AT
THIS TIME...FORECAST RAINFALL AMOUNTS OF 1-1.25 INCHES CAN BE
EXPECTED ACROSS THE FORECAST AREA. THIS MAY CAUSE SOME WITHIN BANK
RISES ON AREA RIVERS...HOWEVER...NO FLOODING IS EXPECTED AT THIS
TIME.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...WETENKAMP
HYDROLOGY...DTJ



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