Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 281725
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1225 PM CDT SUN JUN 28 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 244 AM CDT SUN JUN 28 2015

TALE OF TWO HALVES FOR THIS WEEKEND AS WE CLOSE ON A WET NOTE.

HIGH AMPLITUDE FLOW REMAINS IN PLACE WITH NORTHWEST FLOW ACROSS
NORTH CENTRAL U.S. AND WESTERN GREAT LAKES. NEXT IN LONG LINE OF
SHORT WAVE TROUGHS IS MOVING ACROSS MINNESOTA EARLY THIS MORNING
SPARKING SUB-SEVERE CONVECTION. AS THIS FEATURE MOVES SOUTHEAST THIS
MORNING EXPECT SHOWERS AND THUNDERSTORMS TO OVERTAKE MOST OF THE
AREA...LINGERING INTO THIS EVENING AS WAVE DIVES INTO UPPER TROUGH.

REGARDING ANY SEVERE WEATHER POTENTIAL LATER TODAY...TIMING OF THIS
WAVE IS FAR MORE FAVORABLE SOUTH OF THE AREA. AMOUNT OF INSTABILITY
WILL BE MAIN FACTOR FOR US. NAM MODEL RUNS CONTINUE TO BE MORE
ROBUST WITH INSTABILITY THAT BUILDS AHEAD OF WAVE AND ASSOCIATED
SURFACE FEATURES...BUT PUTTING MORE WEIGHT IN MORE CONSERVATIVE
GFS/ECMWF GIVEN THAT SHOWERS WILL BE OVER MOST OF AREA BEFORE MLCAPE
CAN BUILD. SHORT WAVE ITSELF IS FAIRLY STRONG AND HAS SMALL AREA OF
DECENT SHEAR. BEST SHEAR VALUES ACROSS SOUTHERN AREAS ARE BEFORE ANY
CAPE BUILDS WHICH SUPPORTS HIGHER RISK OF SEVERE TO THE SOUTH OF THE
AREA LATER TODAY. WILL MENTION A RISK FOR A STRONG STORM IN SOUTHERN
TIER OF COUNTIES.

RAIN AMOUNTS COULD REACH AN INCH IN PLACES WITH SOME OF THE HEAVIER
SHOWERS BUT SYSTEM SHOULD REMAIN FAIRLY PROGRESSIVE. HIGH
TEMPERATURES REMAIN UNDERCUT TODAY WITH ALL THE CLOUD COVER AND
RAIN...AND COULD STILL BE TOO WARM.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 244 AM CDT SUN JUN 28 2015

LIKE PREVIOUS DISCUSSIONS HAVE MENTIONED...LOOKING FOR RAIN FREE
PERIODS IN THIS FORECAST REGIME IS TOUGH CONSIDERING SEEMINGLY
ENDLESS FLOW OF SHORT WAVE TROUGHS.

NEXT WAVE TO DROP INTO WESTERN GREAT LAKES MONDAY AND WITH STEEP MID-
LEVEL LAPSE RATES...SUBTLE LIFT WILL BE ENOUGH TO GENERATE FAIRLY
WIDESPREAD CONVECTION. DEEP SHEAR COULD AID A FEW STRONGER
THUNDERSTORMS AS WELL BUT ACTIVITY MIGHT IMPACT AREA MORE INTO THE
EVENING WHEN THINGS BEGIN TO BECOME MORE STABLE.

ANOTHER SUBTLE FEATURE COULD GENERATE MORE SHOWERS/STORMS ON TUESDAY
BUT THIS SHOULD BE MORE ON WISCONSIN SIDE...CLOSER TO LAKE MICHIGAN
AS BRIEF UPSTREAM RIDGING BUILDS IN.

SAD TO SAY BUT THE CYCLE LOOKS TO CONTINUE UP TO THE 4TH OF JULY.
POOR RUN TO RUN CONSISTENCY IN MEDIUM RANGE AS MODELS STRUGGLE WITH
SUBTLE WAVES WITH OFF AND ON RAIN CHANCES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1225 PM CDT SUN JUN 28 2015

PLAN ON SCATTERED SHRA/TS THIS AFTERNOON AS A MID-LEVEL TROUGH
DROPS THROUGH THE REGION. DUE TO THE SCATTERED NATURE OF THIS
CONVECTION...WENT WITH VCTS AT BOTH KRST/KLSE TAF SITES AFTER 19Z
WITH MAINLY VFR CONDITIONS EXPECTED. EXPECT SOME AMENDMENTS AS
THE AFTERNOON WEARS ON IF SHRA/TS ENCROACH THE AREODROMES.THIS
CONVECTION IS THEN EXPECTED TO DIE OFF TOWARD 02Z WITH LOSS OF
SURFACE HEATING. LIGHT WINDS OVERNIGHT AND A MOIST LOWER BOUNDARY
LAYER FROM TODAYS RAINFALL WILL LEAD TO IDEAL STRATUS/FOG
CONDITIONS OVERNIGHT. HIGHER CONFIDENCE IS AT KLSE WHERE WINDS
ARE EXPECTED TO DECOUPLE MORE IN THE RIVER VALLEY.

&&

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

$$

SHORT TERM...SHEA
LONG TERM....SHEA
AVIATION...DAS



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