Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 281128
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
628 AM 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 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 628 AM CDT SUN JUN 28 2015

LOW PRESSURE...A COLD FRONT AND A RATHER VIGOROUS MID LEVEL
SHORTWAVE CONTINUE TO MOVE SOUTHEAST TOWARD THE AREA EARLY THIS
MORNING. ONE BAND OF SCT MAINLY -SHRA MOVING THRU THE KLSE AREA IN
THE 11-14Z TIME FRAME...WITH A CLUSTER OF -TSRA SET TO MOVE THRU THE
KRST AREA IN THE 12-14Z TIME FRAME. VFR CIGS EXPECTED WITH SOME MVFR
VSBYS IN ANY HEAVIER RAIN CORES. PERIODS OF SHRA/TSRA EXPECTED THRU
TODAY AS THE LOW/FRONT/SHORTWAVE SLOWLY MOVE SOUTHEAST AND ACROSS
THE AREA TODAY. AS THESE LATER ROUNDS OF SHRA/TSRA PASS...APPEARS
BULK OF CIGS/VSBYS TO BE VFR WITH SOME MVFR CIGS/VSBYS IN HEAVIER
RAIN CORES. RATHER THAN TEMPO THIS THRU AN EXTENDED PORTION OF THE
TAFS TODAY...15Z TO AROUND 00Z...LEFT PRECIP MENTIONS A BOTH
KRST/KLSE AS VCSH/VCTS FOR NOW. WILL HAVE TO MONITOR THRU THE DAY
AND AMEND AS NEED WHEN A MORE PRONOUNCED ROUND OF SHRA/TSRA WOULD
MOVE ACROSS ONE OF THE TAF SITES.

ONCE THE WAVE/LOW PASS LATER TODAY...GENERALLY GOOD VFR EXPECTED
THIS EVENING INTO THE OVERNIGHT HOURS. SIGNAL FOR SOME LATE NIGHT BR
AT BOTH KRST/KLSE WITH LIGHT WINDS/MOSTLY CLEAR-PARTLY CLOUDY SKIES
AND THE RAINS. ADDED AN MFVR BR MENTION AFTER 08-09Z AT BOTH SITES.

&&

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

$$

SHORT TERM...SHEA
LONG TERM....SHEA
AVIATION.....RRS


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