Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 170356
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1056 PM CDT WED APR 16 2014

.UPDATE...
ISSUED AT 957 PM CDT WED APR 16 2014

DRY AIR PRESENT ON THE 00Z GRB SOUNDING IS HAVING A SIGNIFICANT
IMPACT ON PRECIPITATION TO THE EAST SIDE OF THE LOW PRESSURE
SYSTEM IN NORTH CENTRAL IOWA. SO FAR THE BULK OF THE PRECIPITATION
HAS BEEN CONFINED TO THE COLD CONVEYOR BELT...AND EVEN THAT HAS
BEEN VERY SLOW TO PROGRESS EASTWARD. HAVE LOWERED PRECIPITATION
CHANCES FOR THE NEXT FEW HOURS...TOWARDS THE IDEA TOO OF THE
RAP/HRRR. ADVISORY FOR TAYLOR COUNTY STILL ON TRACK...WITH THE
BULK OF THE SNOW OCCURRING BETWEEN 06-12Z...AND IF THE LATEST RAP
IS CORRECT...BETWEEN 10-12Z.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 307 PM CDT WED APR 16 2014

MAIN FORECAST CONCERNS ARE ON SNOW TONIGHT OVER NORTH CENTRAL
WISCONSIN. FOCUS THEN TURNS TO RAIN CHANCES THIS WEEKEND.

LATEST SURFACE OBSERVATIONS SHOWED LOW PRESSURE CENTERED NEAR SIOUX
CITY WITH A WARM FRONT EXTENDING NORTHEAST THROUGH SOUTHERN
MINNESOTA INTO NORTH CENTRAL WISCONSIN. THE LOW WILL CONTINUE
MOVING NORTHEAST LATE THIS AFTERNOON INTO TONIGHT WITH SNOW
FALLING ON THE NORTHERN AND NORTHWEST SIDE OF THE LOW TRACK. THE
SNOW WILL CONTINUE TO BE HEAVY AT TIMES ESPECIALLY OVER NORTHWEST
WISCONSIN. NORTH CENTRAL WISCONSIN HAS BEEN EXPERIENCING SNOW
TODAY HOWEVER LOCATIONS SOUTH OF THE WISCONSIN HIGHWAY 10 CORRIDOR
HAVEN/T SEEN ANY PRECIPITATION BEING POSITIONED IN THE WARM
SECTOR THROUGH MUCH OF THE DAY. THESE ARES COULD SEE SOME LIGHT
PRECIPITATION ALONG THE COLD FRONT TONIGHT OR ON THE BACK SIDE OF
THE LOW AS IT TRACKS INTO NORTH CENTRAL WISCONSIN LATER TONIGHT. 4
INCHES OF SNOW HAS BEEN REPORTED SO FAR TODAY IN NORTHWEST TAYLOR
COUNTY. PLAN ON AN ADDITIONAL 1 TO 3 INCHES TONIGHT AS THE
DEFORMATION ZONE SLIDES INTO TAYLOR COUNTY. WILL CONTINUE THE
WINTER WEATHER ADVISORY IN TAYLOR BUT HAVE DECIDED TO CANCEL IT
FOR CLARK COUNTY. FORECAST SOUNDINGS SHOW ICE BEING LOST ALOFT
TONIGHT BEFORE THE PRECIPITATION EXIT. ANY LINGERING
PRECIPITATION  LATE TONIGHT INTO EARLY THURSDAY MORNING COULD
SWITCH OVER TO DRIZZLE OR FREEZING DRIZZLE WHERE SURFACE
TEMPERATURES ARE COLD ENOUGH. HOWEVER...WITH THE SOUTHERLY FLOW
KEEPING TEMPERATURES MAINLY ABOVE FREEZING TONIGHT FREEZING
DRIZZLE SHOULDN/T BE A PROBLEM TONIGHT. A MOSTLY CLOUDY AND
UNSEASONABLY COOL DAY IS IN STORE FOR THE REGION ON THURSDAY IN
THE WAKE OF THE LOW WITH HIGHS RANGING FROM THE UPPER 30S OVER
NORTH CENTRAL WISCONSIN TO THE MID TO UPPER 40S ACROSS NORTHEAST
IOWA.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 307 PM CDT WED APR 16 2014

COOL HIGH PRESSURE BUILDS IN THURSDAY NIGHT PROVIDING PARTLY CLOUDY
SKIES AND CHILLY CONDITIONS. PLAN ON OVERNIGHT LOWS FALLING INTO THE
20S. THE HIGH IS EXPECTED TO SLIDE EAST ON FRIDAY AS UPPER RIDGING
BUILDS IN FROM THE NORTHERN PLAINS. A WEAK SHORTWAVE SLIDES OVER THE
REGION DURING THE DAY ON FRIDAY AS WARM AIR ADVECTION INCREASES FROM
850-700 MB...WHICH COULD LEAD TO SOME LIGHT PRECIPITATION OVER
PORTIONS OF NORTHEAST IOWA AND SOUTHEAST MINNESOTA BUT THE BULK OF
THIS ACTIVITY LOOKS TO STAY WEST OF THE INTERSTATE 35 CORRIDOR. IF
THE PRECIPITATION  OCCURS BEFORE MID MORNING IT WOULD LIKELY FALL
IN THE FORM OF VERY LIGHT SNOW. IF IT OCCURS IN THE LATE MORNING
INTO THE AFTERNOON HOURS TEMPERATURES WOULD BE WARM ENOUGH FOR THE
PRECIPITATION TYPE TO BE RAIN.

THE RIDGE SLIDES OVER THE UPPER MISSISSIPPI RIVER VALLEY FRIDAY
NIGHT INTO SATURDAY MORNING AS A SURFACE TROUGH DEVELOPS OVER THE
PLAINS PLACING THE FORECAST AREA IN SOUTHERLY FLOW AT THE SURFACE. A
WEAK COLD FRONT WILL SLIDE SOUTHEAST INTO THE REGION SATURDAY
AFTERNOON INTO SATURDAY EVENING AS LOW PRESSURE TRACKS ACROSS
SOUTHERN MANITOBA. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
ALONG AND AHEAD OF THE BOUNDARY. THE BOUNDARY THEN EDGES SOUTH
AND BECOMES NEARLY STATIONARY OVER NORTHEAST IOWA AND SOUTHERN
MINNESOTA. FORECAST SOUNDINGS ARE SHOWING VERY WEAK CAPE
VALUES...ONLY YIELDING AROUND 100 MB OF CAPE WHEN LIFTING FROM 700
MB. THINKING THIS SHOULD BE ENOUGH TO SEE SOME LIGHTING OUT OF
THIS ACTIVITY. PRECIPITABLE WATER VALUES APPROACH 1.3 INCHES. IT
APPEARS MOST AREAS WILL SEE BETWEEN 0.4 AND 1 INCH OF RAINFALL
FROM LATE SATURDAY AFTERNOON THROUGH SUNDAY.THE BOUNDARY FINALLY
SHIFTS SOUTHEAST OF THE REGION LATE MONDAY INTO SUNDAY AS A MUCH
HIGHER AMPLITUDE RIDGE BUILDS INTO THE PLAINS AND UPPER MIDWEST AS
A LARGE TROUGH DIGS INTO THE WEST COAST. THIS RIDGE LOOKS TO
BRING MUCH WARMER TEMPERATURES TO THE REGION ALONG WITH AN ACTIVE
PATTERN...ESPECIALLY DURING THE MIDDLE TO LATER PART OF NEXT WEEK
ALSO...THE WEST COAST TROUGH DRAWS CLOSER AND SOUTHWEST FLOW ALOFT
ATTEMPTS TO EDGE INTO THE UPPER MISSISSIPPI RIVER VALLEY WHICH
WOULD ALSO FAVOR AN ACTIVE WEATHER PATTERN. WILL HAVE TO KEEP A
CLOSE EYE ON THIS OVER THE NEXT FEW MODEL RUNS. HIGH TEMPERATURES
NEXT WEEK LOOK TO CLIMB BACK INTO THE 60S WITH THE POTENTIAL TO
SEE SOME LOW TO MID 70S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1056 PM CDT WED APR 16 2014

A BAND OF RAIN CONTINUES TO IMPACT SOUTH CENTRAL MINNESOTA INTO
RST...ON THE NORTHWEST SIDE OF LOW PRESSURE NEAR MASON CITY IOWA.
DRY EASTERLY FLOW HAS HELPED KEEP VISIBILITIES AND CEILINGS VFR AT
THIS POINT FOR BOTH TAF SITES. HOWEVER...AS THE LOW PASSES OFF TO
THE EAST...EXPECT CEILINGS TO GO DOWNHILL...WITH IFR CEILINGS LOOKING
LIKELY FOR RST BETWEEN 08-12Z. LSE BEING IN THE VALLEY WILL HELP
TO KEEP THE CEILINGS FROM FALLING BELOW IFR THERE. THE RAIN SHOULD
PASS THROUGH AND OUT OF BOTH TAF SITES BY 08Z. LOOK FOR CEILINGS
TO CLIMB TO VFR...DUE TO THE CLOUDS SCATTERING OUT FROM DRY AIR
FLOWING IN...TO OCCUR BETWEEN 18-19Z ON THURSDAY. VFR CONDITIONS
WILL THEN PERSIST THROUGH THE EVENING.

WINDS ARE ANOTHER ISSUE WITH THE PASSING OF THE LOW. PRESENTLY
SOUTHEAST WINDS HAVE BEEN BLOWING 10-15 KT...WITH GUSTS UPWARDS
OF 20 KT AT LSE. LOW LEVEL WIND SHEAR CONTINUES AT LSE DUE TO WINDS
NEAR 2000 FT ABOVE THE SURFACE BETWEEN 45-55 KT...BUT THESE SHOULD
END BY 08Z. AFTER THE LOW PASSES...WINDS WILL TURN WEST AND
EVENTUALLY NORTHWEST BY 12Z...WITH SPEEDS OF 10-15 KT AND GUSTS OF
20-25 KT. EXPECT THE WIND GUSTS TO DIMINISH AROUND MID-DAY AS THE
PRESSURE GRADIENT WEAKENS...WITH FURTHER DIMINISHING IN THE
EVENING AS HIGH PRESSURE BUILDS IN.

&&

.HYDROLOGY...
ISSUED AT 307 PM CDT WED APR 16 2014

RUNOFF FROM RECENT RAINFALL AND SNOWMELT HAS CREATED ELEVATED
RIVER LEVELS ALONG THE MISSISSIPPI RIVER. MINOR FLOODING IS
EXPECTED AT WABASHA AND MCGREGOR AND FLOOD WARNINGS ARE IN
EFFECT.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 7 AM CDT THURSDAY FOR WIZ017.

MN...NONE.
IA...NONE.
&&

$$

UPDATE...AJ
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
HYDROLOGY...WETENKAMP



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