Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 301713
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1213 PM CDT SAT MAY 30 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 255 AM CDT SAT MAY 30 2015

UPPER LEVEL SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT MAKING STEADY
ALBEIT SOMEWHAT SLOW PROGRESS EAST/SOUTHEAST ACROSS THE REGION EARLY
THIS MORNING. SHOWERS WERE WIDESPREAD AHEAD OF IT...WITH A LINE OF
CONVECTION RIDING ALONG THE FRONT.

THE FRONT SINKS ACROSS ILL BY LATE MORNING BUT THE TROUGH AXIS ISN/T
SLATED TO CLEAR THE FORECAST AREA TIL THIS EVENING. NAM POINTS TO
SOME ELEVATED FRONTOGENETIC FORCING ACROSS NORTHEAST IA/SOUTHWEST WI
THROUGH THE BETTER PART OF THE DAY...BUT MINIMAL IF ANY INSTABILITY
AND NON-IMPRESSIVE LAPSE RATES. THE NAM WOULD HANG ONTO SOME RAIN
CHANCES ACROSS THE FAR SOUTH INTO THE AFTERNOON...BUT MOST MESO
MODELS WANT TO CLEAR IT BY 18Z. GOING TO SIDE THE FORECAST TOWARD
THESE MORE PROGRESSIVE SOLUTIONS.

HIGH PRESSURE BUILDS IN LATER TODAY AND HANGS AROUND THE GREAT LAKES
THROUGH MONDAY. GFS/NAM/ECMWF ALL SUGGEST THE HIGH WILL SERVE TO
BOUNCE ANY POTENTIAL SHORTWAVES SOUTH/NORTH OF THE FORECAST AREA
DURING THIS TIME...KEEPING THE AREA DRY. WILL CONTINUE THIS TREND.

TEMPERATURES ARE GOING TO TAKE A TUMBLE FOR THE NEXT FEW DAYS...WITH
850 BM TEMPS FALLING FROM NEAR 12C LAST NIGHT...TO 4 C BY 00Z MON.
HIGHS WILL MOSTLY BE IN THE 60S THROUGH MONDAY. IN ADDITION...WITH
CLEARING SKIES TONIGHT...RADIATIONAL COOLING COULD RESULT IN SOME
MID 30 LOWS FOR PARTS OF CENTRAL/NORTHERN WI. PATCHY/AREAS FROST IS
POSSIBLE. WINDS COULD STAY ABOVE 5 KTS THOUGH...WHICH LIMITS
CONFIDENCE IN A WIDESPREAD EVENT. PER COORDINATION WITH SURROUNDING
OFFICES...WILL ISSUE FROST ADV FOR TAYLOR COUNTY IN NORTH-CENTRAL
WI. IF WIND SPEEDS LOOK LOWER...THE ADV COULD BE EXPANDED INTO PARTS
OF CENTRAL WISCONSIN WHERE COLD AIR DRAINAGE IS COMMON.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 255 AM CDT SAT MAY 30 2015

EXTENDED FORECAST HINGES ON THE STRENGTH OF THE LONG WAVE RIDGE
BUILDING ANTICIPATED FOR MUCH OF THE CENTRAL U.S...WILL IT BE ENOUGH
TO HOLD AT BAY THE VARIOUS PERTURBATIONS A WEST COAST TROUGH WILL
SEND AT US.

MODELS ALREADY AT ODDS WITHIN AND BETWEEN EACH OTHER...AND EXPECT
THE DIFFERENCES TO PERSIST FOR AT LEAST THE NEXT COUPLE DAYS. THIS
LOWERS FORECAST CONFIDENCE IN THE DRY-NOT DRY QUESTION. WILL HAVE TO
LEAN ON CONSENSUS AS A RESULT...WHICH PAINTS A LOT OF SMALL
POPS...ESPECIALLY WEST AND NORTH.

AS IT STANDS NOW...THE GFS FAVORS THE DRIER SOLUTION...USING THE
RIDGE TO KEEP/SHUNT PCPN CHANCES WEST/NORTH. THIS IS ESPECIALLY
EVIDENT ON WED WHERE THE EC/GEM TAKES A SHORTWAVE THEY ALL FORECAST
INTO THE UPPER MISSISSIPPI RIVER VALLEY...BRINGING THE THREAT FOR
SHOWERS/STORMS. THE EC THEN STAYS THE WET MODEL WITH ANOTHER
SHORTWAVE WORKING IN CONCERT WITH A SFC FRONT TO CONTINUE THE RAIN
THREAT INTO FRIDAY MORNING. THE GFS WOULD FINALLY BREAK INTO THE
RIDGE ON FRIDAY...CONTINUING SOME SMALL PCPN CHANCES INTO SAT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1213 PM CDT SAT MAY 30 2015

MVFR DECK REMAINS OVER THE AREA IN THE WAKE OF THE COLD FRONT THAT
WENT THROUGH OVERNIGHT. THE BACK EDGE OF THE CLOUDS ARE SLOWLY
WORKING EAST ACROSS MINNESOTA...BUT STILL EXPECT IT WILL TAKE MOST
OF THE AFTERNOON BEFORE THESE CLOUDS WILL START TO SCATTER OUT.
BASED ON THE 30.15Z RAP SOUNDINGS...THE CLEARING SHOULD OCCUR LATE
THIS AFTERNOON AT KRST AND EARLY THIS EVENING AT KLSE. WITH THE
RECENT RAINS...CONCERNED ABOUT FOG POTENTIAL OVERNIGHT WITH ALL
THE LOW LEVEL MOISTURE AND THE CLEARING SKIES. HOWEVER...IT LOOKS
LIKE THE WINDS WILL REMAIN BETWEEN 5 AND 10 KNOTS OUT OF THE
NORTHEAST AS HIGH PRESSURE SLOWLY BUILDS IN FROM CANADA. DEW
POINTS ARE IN THE 30S ACROSS NORTHERN MINNESOTA AND WISCONSIN AND
THE NORTHEAST WINDS SHOULD ADVECT THIS DRIER AIR IN HELPING TO
MITIGATE THE FOG THREAT.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 3 AM TO 8 AM CDT SUNDAY FOR WIZ017.

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

$$

SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04


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