Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 271745
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1245 PM CDT SAT JUN 27 2015

.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 300 AM CDT SAT JUN 27 2015

SEEMS LIKE THIS FORECAST IS ALL ABOUT TRYING TO FIND THOSE RAIN FREE
PERIODS AS HIGHLY AMPLIFIED FLOW AND PESKY NORTHWEST FLOW REGIME
CONTINUES.

CONVECTION FROM FRIDAY DIED OUT QUICKLY DURING THE LATE EVENING BUT
STILL SEEING SOME UPSTREAM WHERE DIFFLUENT FLOW AND NEXT SHORT WAVE
HELPING TO SPARK SCATTERED STORMS ACROSS CANADIAN PRAIRIES. ACTIVITY
LAST FEW DAYS HAS BEEN PRIMARILY AIDED BY WEAK SHORT WAVES WHICH
SEEM TO BE LACKING TODAY. HATE TO WRECK A DRY FORECAST BUT NOT
ENTIRELY CONVINCED IT WILL BE DRY TODAY WITH STEEP MID LEVEL LAPSE
RATES AND NO BIG CHANGE IN AIRMASS. COVERAGE SHOULD BE FAR LESS
THOUGH SO WILL HOLD FOR NOW.

AFOREMENTIONED SHORT WAVE TROUGH IS EXPECTED TO DROP INTO WESTERN
GREAT LAKES NEXT 36 HOURS...WHICH WILL SERVE AS FOCUS FOR MUCH
HIGHER RAIN THREAT STARTING LATE TONIGHT INTO MOST OF SUNDAY.

INCREASING MID LEVEL WINDS ASSOCIATED WITH WAVE...ALONG WITH MODEST
INSTABILITY AHEAD OF FRONT COULD TRIGGER SEVERE THUNDERSTORMS
NORTHWEST OF AREA TONIGHT /SEE SPC DAY 1 OUTLOOK/ BUT TIMING OF WAVE
PASSAGE FAVORS LESS SEVERE WEATHER RISK FOR US. CONVECTION SHOULD
APPROACH EARLY SUNDAY IN A WEAKENING STATE WITH LOW TO NIL MIXED
LAYER CAPE EXPECTED.

AS WAVE ROTATES AROUND SOUTHWEST GREAT LAKES AREA SUNDAY...SHOWERS
AND A FEW THUNDERSTORMS COULD PERSIST UNTIL SUNDAY NIGHT. HIGHER
INSTABILITY LIKELY AHEAD OF WAVE FAVORING ANY SEVERE WEATHER RISK
LIKELY SOUTH OF REGION. DID LOWER TEMPERATURES EVEN FURTHER FOR
SUNDAY THOUGH CONSIDERING CONFIDENCE HIGH WITH WIDESPREAD CLOUDS AND
RAIN.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 300 AM CDT SAT JUN 27 2015

NO BIG PATTERN CHANGE NOTED FOR NEXT WEEK WITH OCCASIONAL SHORT
WAVES IN NORTHWEST FLOW. THIS COULD LEAD TO SCATTERED...MAINLY
DIURNAL CONVECTION THROUGH A LOT OF THE PERIOD MAINTAINING A NEED
FOR CHANCE RAIN THREATS. DIFFERENCES BETWEEN 27.00Z MODEL RUNS ALSO
COMPLICATE MATTERS WITH DIFFICULTY RESOLVING EACH MINOR WAVE.

MONDAY AND TUESDAY BOTH COULD HAVE WEAK FORCING FROM WAVES...
AND COMBINED WITH STEEP LAPSE RATES...MORE AFTERNOON/EVENING
CONVECTION. IDEA OF HIGH PRESSURE TRYING TO BUILD IN FOR WEDNESDAY
NIGHT STILL CONSISTENT WHICH COULD FOLLOW INTO THURSDAY AS WELL.
STRONGER LATE WEEK SHORT WAVE AND ASSOCIATED FRONT LIKELY TO SPAWN
HIGH RAIN THREATS...AND WILL HAVE TO BE WATCHED FOR ANY INSTABILITY
LEADING TO SEVERE WEATHER RISK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1244 PM CDT SAT JUN 27 2015

HIGH PRESSURE WILL PROVIDE MOSTLY CLEAR SKIES THROUGH THIS
EVENING...AND THEN A SHORT WAVE TROUGH /CURRENTLY OVER MANITOBA/
WILL BRING AROUND OF SHOWERS AND SCATTERED STORMS TO THE AREA.
THESE WILL MOVE INTO KRST AROUND 28.09Z AND KLSE AROUND 28.11Z.
BOTH CEILINGS AND VISIBILITIES WILL BE MAINLY VFR FOR THE TIME
PERIOD. HOWEVER THEY MAY BECOME BRIEFLY MVFR IN THE HEAVIER
SHOWERS AND STORMS. THE WEST WINDS WILL GRADUALLY SHIFT TO SOUTH
BY THIS EVENING AND REMAIN FROM THAT DIRECTION THROUGH THE
REMAINDER OF THE TAF PERIOD. WIND SPEEDS WILL REMAIN PRIMARILY
LESS THAN 10 KNOTS.

&&

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

$$

SHORT TERM...SHEA
LONG TERM....SHEA
AVIATION...BOYNE


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