000
FXUS63 KARX 181935
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
235 PM CDT FRI JUL 18 2014

.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 235 PM CDT FRI JUL 18 2014

WATER VAPOR SATELLITE IMAGERY SHOWING A MID-LEVEL TROUGH OF LOW
PRESSURE EXTENDING FROM SOUTHERN LAKE MICHIGAN THROUGH THE MID-
MISSISSIPPI RIVER VALLEY REGION WHILE WEAK RIDGING WAS TAKING PLACE
ACROSS NORTHERN WI ONTO ONTARIO. VISIBLE SATELLITE SHOWS QUITE A BIT
OF CUMULUS WITH DAYTIME HEATING AND COOLER AIR RESIDING ALOFT. SO
FAR...NO PRECIPITATION ECHOES WERE NOTED ON RADAR AND PROBABLY
SHOULD REMAIN THAT WAY WITH RAP BUFKIT SHOWING A FAIRLY GOOD CAP
RIGHT AROUND 700MB. OTHERWISE...TEMPERATURES ACROSS THE AREA RANGED
FROM THE MIDDLE 70S TO A FEW 80 DEGREE READINGS.

QUIET NIGHT ON TAP FOR THE AREA WITH SOME PASSING CUMULUS. LOOK FOR
LOWS IN THE UPPER 50S TO THE LOWER 60S.

ATTENTION THEN TURNS TO AN INCOMING MID-LEVEL TROUGH FROM THE
NORTHERN PLAINS AND WEAKENING SURFACE COLD FRONT ON SATURDAY. MODEL
CONSENSUS 0-1KM MLCAPE BUILDS INTO THE 600-1200J/KG RANGE FROM SOUTH
CENTRAL MN INTO NORTH CENTRAL WI AS THE WAVE PASSES OVERHEAD. NOT
MUCH FOR SURFACE CONVERGENCE BUT BELIEVE THERE WILL BE ENOUGH
INSTABILITY AROUND TO GENERATE ISOLATED-SCATTERED SHOWER/THUNDER
ACTIVITY. PLAN ON HIGHS SIMILAR TO TODAY...IN THE UPPER 70S TO THE
LOWER 80S.

WILL CONTINUE TO SEE A SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDER
ACROSS PORTIONS OF NORTH CENTRAL WI SATURDAY NIGHT AS THE TAIL-END
OF THE MID-LEVEL WAVE AND SURFACE COLD FRONT SLIP ACROSS THAT AREA.
OVERNIGHT LOWS LOOK TO BE IN THE 60-65 DEGREE RANGE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 235 PM CDT FRI JUL 18 2014

NAM/GFS/ECMWF/GEM ALL IN GOOD AGREEMENT IN RIDGE BUILDING OVER THE
AREA ON SUNDAY AS ANOTHER MID-LEVEL TROUGH GETS DEFLECTED NORTHWEST
INTO NORTHERN MN. THIS SHOULD KEEP ANY SHOWER/THUNDER CHANCES UP
ACROSS THAT AREA...WITH ARX FORECAST AREA REMAINING DRY.
OTHERWISE...A BIT WARMER AND SLIGHTLY MORE HUMID CONDITIONS EXPECTED
WITH HIGHS IN THE 80-85 DEGREE RANGE AND DEW POINTS CREEPING INTO
THE MIDDLE AND UPPER 60S.

MODELS SHOWING GOOD CONSENSUS WITH 850-700MB WAA/ISENTROPIC
LIFT/MOISTURE TRANSPORT INTO THE AREA AHEAD OF A WARM FRONT LIFTING
OUT OF THE NORTHERN PLAINS/UPPER MISSISSIPPI RIVER SUNDAY NIGHT.
LOOKS LIKE ENOUGH FORCING FOR SHRA/THUNDER CHANCES.

THE AREA LOOKS TO BE IN THE WARM SECTOR/SOUTH OF THE WARM FRONT ON
MONDAY. NAM BUFKIT SHOWING FAIRLY GOOD CAP BUILDING IN THE 800-850MB
LAYER AS MID-LEVEL RIDGE BUILDS. THIS SHOULD SHUT DOWN
SHOWER/THUNDER CHANCES. OTHERWISE...LOOKS WARMER AND INCREASINGLY
HUMID WITH HIGHS IN THE 85-90 DEGREE RANGE AND DEW POINTS IN THE
LOWER 70S. WITH THESE TEMPS/DEW POINTS...HEAT INDICES SHOULD BE IN
THE 95-100 DEGREE RANGE FOR AREAS ALONG/WEST OF THE MISSISSIPPI
RIVER.

SHOWER AND THUNDERSTORM CHANCES WILL BE ON THE INCREASE MONDAY NIGHT
THROUGH TUESDAY NIGHT AS MODELS ARE COMING IN BETTER AGREEMENT IN
BRINGING A FAIRLY SIGNIFICANT MID-LEVEL SHORTWAVE TROUGH AND
ATTENDANT SURFACE LOW ACROSS THE AREA. RIGHT NOW IT APPEARS THE
BEST FORCING WILL BE FOCUSED ACROSS AREAS ALONG AND NORTH OF I-90.
SOME LINGERING SHOWER/THUNDERSTORM CHANCES WILL CONTINUE INTO
WEDNESDAY AS WELL AS COOLER CYCLONIC FLOW RESIDES ACROSS THE AREA.

THURSDAY AND FRIDAY LOOK COOLER AS THE REGION BECOMES DOMINATED BY
NORTHWEST FLOW ALOFT. SHOWER/THUNDER CHANCES RETURN FRIDAY ACROSS
THE WEST AS THE MODELS SHOW A WARM FRONT APPROACHING FROM THE
PLAINS. OTHERWISE...LOOK FOR HIGHS THURSDAY AND FRIDAY IN THE 75-80
DEGREE RANGE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1243 PM CDT FRI JUL 18 2014

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. LOW LEVEL
MOISTURE COMBINED WITH A SERIES OF WEAK UPPER LEVEL DISTURBANCES
WILL GENERATE SCATTERED TO BROKEN CUMULUS AT THE TAF SITES THIS
AFTERNOON INTO EARLY THIS EVENING. PLAN ON CLOUD BASES RANGING
FROM 4-8 KFT. A TIGHT PRESSURE GRADIENT OVER THE REGION WILL
PRODUCE SOUTH/SOUTHWEST WINDS OF 10 TO 13 KTS WITH GUSTS
APPROACHING 20 KTS AT TIMES. THE WINDS WILLS SUBSIDE TO 6-8 KTS
THIS EVENING.

&&

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

$$

SHORT TERM...DAS
LONG TERM....DAS
AVIATION...WETENKAMP