Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 170432
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1130 PM CDT THU OCT 16 2014

.SHORT TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 235 PM CDT THU OCT 16 2014

MAIN FORECAST CONCERN FOCUSED ON FRIDAY WITH WINDS AND SHOWER
CHANCES.

SURFACE MAP THIS AFTERNOON HAD A RIDGE OF HIGH PRESSURE EXTENDING
FROM WESTERN KY THROUGH WI. MEANWHILE...A DEEP 997MB LOW WAS LOCATED
ALONG THE MN/ND BORDER. CURRENT VISIBLE SATELLITE IMAGERY SHOWING
ARX FORECAST AREA PRETTY MUCH VOID OF CLOUDS. ABUNDANT SUNSHINE AND
WARM AIR ADVECTION ON THE BACKSIDE OF THE HIGH AND IN ADVANCE OF THE
LOW WAS PUSHING TEMPERATURES WELL INTO THE 60S.

MODELS IN VERY GOOD AGREEMENT WITH UPPER LEVEL/SURFACE FEATURES IN
THE SHORT TERM LENDING TO FAIRLY HIGH FORECAST CONFIDENCE.

FOR TONIGHT...LOOK FOR THE LOW ALONG THE MN/ND BORDER TO MOVE INTO
NORTHERN WI AROUND MIDNIGHT AND NORTHERN LAKE MICHIGAN BY DAYBREAK.
THIS DRAGS A DRY COLD FRONT THROUGH THE REGION OVERNIGHT WITH MAIN
IMPACT BEING A SHIFT IN THE WINDS TO THE WEST/NORTHWEST...BECOMING
GUSTY BETWEEN 09-12Z. LOOKS LIKE ANY SHOWER CHANCES MORE ASSOCIATED
WITH 850-300MB PV-ADVECTION/STEEPENING LOW LEVEL LAPSE RATES HOLD
OFF UNTIL AFTER DAYBREAK AND REMAINING MAINLY ALONG AN NORTH OF I-
90. SECOND PART OF THIS STORM SYSTEM WILL BE GUSTY NORTHWEST WINDS
THROUGH THE DAY FRIDAY ON THE BACKSIDE OF THE LOW IN COLD AIR
ADVECTION. EXPECTING SUSTAINED WINDS IN THE 15-20 MPH RANGE WITH
GUSTS AROUND 30 MPH ACROSS THE MORE WIND PRONE AREAS. WITH HIGHS
ONLY TOPPING OFF IN THE 50S...CLOUDS/SCATTERED SHOWERS/GUSTY
NORTHWEST WINDS WILL MAKE FOR A FAIRLY RAW DAY.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 235 PM CDT THU OCT 16 2014

A SECONDARY MID-LEVEL TROUGH/SURFACE COLD FRONT DROPS THROUGH THE
AREA FRIDAY NIGHT FOR A CONTINUED CHANCE OF SHOWERS. APPEARS THE
SHOWER CHANCES WOULD BE CONFINED MAINLY ALONG/NORTH OF I-94.

HIGH PRESSURE SETTLES OVER THE REGION SATURDAY INTO SATURDAY NIGHT
FOR COOL/DRY CONDITIONS. LOOK FOR HIGHS IN THE UPPER 40S TO THE
MIDDLE 50S. LOWS SATURDAY NIGHT ARE EXPECTED TO DIP DOWN INTO THE
UPPER 20S ACROSS CENTRAL WI AND IN THE LOWER/MIDDLE 30S ELSEWHERE.

MODELS CONSISTENT ON A MID-LEVEL TROUGH/SURFACE LOW DROPPING
SOUTHEAST FROM CANADA INTO THE U.P SUNDAY/SUNDAY NIGHT. APPEARS
THERE WILL BE BE A GOOD WING OF WARM AIR ADVECTION/ISENTROPIC
UPGLIDE ASSOCIATED WITH THE WAVE. HOWEVER...SOUNDINGS LOOK VERY DRY
IN THE LOWER LAYERS WITH BEST CHANCE FOR COLUMN SATURATION AGAIN
MAINLY ALONG AND NORTH OF I-94. WILL KEEP SMALL CHANCE OF SHOWERS
GOING ACROSS THAT AREA GIVEN THIS SIGNAL. OTHERWISE...PLAN ON HIGHS
SUNDAY IN THE 50S WITH OVERNIGHT LOWS SUNDAY NIGHT IN THE 40S.

APPEARS THE REST OF THE PERIOD...MONDAY THROUGH THURSDAY...WILL BE
QUIET AS A RIDGE OF HIGH PRESSURE BUILD INTO THE CENTRAL CONUS. LOOK
FOR HIGHS THROUGH THIS PERIOD IN THE 50S WITH OVERNIGHT LOWS IN THE
30S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1130 PM CDT THU OCT 16 2014

AN UPPER LEVEL SHORTWAVE TROUGH WAS MARCHING ACROSS NORTHERN MN LATE
THIS EVENING...AND IS EXPECTED TO DROP SOUTHEAST OVER THE EASTERN
GREAT LAKES BY FRI NIGHT. THE BULK OF THE FORCING WITH THIS FEATURE
WILL SLIDE ACROSS NORTHERN PARTS OF MN/WI...AND THAT IS WHERE THE
GREATEST RAIN CHANCES WILL LIE. COULD SEE A FEW SHOWERS PASS ACROSS
KRST/KLSE AS WESTWARD HANGING SFC TROUGH DROPS ACROSS THE AREA. VCSH
WOULD PROBABLY COVER IT...BUT CONFIDENCE NOT HIGH ENOUGH TO INCLUDE
IN FORECAST AT THIS TIME. WOULD BE MINIMAL IMPACT.

WHAT THE LOW LACKS IN PCPN IMPACTS IT WILL BRING IN CLOUDS. A BAND
OF 1.5-2.5 KFT CIGS IS CURRENTLY OVER THE DAKOTAS/WESTERN MN...WEST
OF THE SYSTEM/S LOW CENTER. MODELS BRING THE LOW LEVEL SATURATION
INTO KRST BETWEEN 06-09Z...AND TOWARD 12Z FOR KLSE. EXPECT SOME
DIURNAL BUMP DURING THE DAY...BUT CIGS LIKELY TO STAY MVFR THROUGH
THE DAY. SOME SUGGESTIONS IN THE BUFKIT SOUNDINGS THAT THE CIGS WILL
LIFT/BREAK UP TO A SCATTERED AND/OR VFR CIG DECK FRI EVENING.
NAM/GFS RH FIELDS...HOWEVER...SUGGEST A SECOND SURGE OF LOW LEVEL
SATURATION RETURNS...AHEAD OF A BIT OF UPPER LEVEL ENERGY DROPPING
DOWN THE BACKSIDE OF THE MEAN TROUGH. CONFIDENCE NOT HIGH IN WHEN/IF
SOME IMPROVEMENT WOULD OCCUR BEFORE THIS...SO WILL HOLD WITH THE
MVFR CIGS THROUGH THE FORECAST PERIOD. HOWEVER...AS THE SHORTWAVE
PASSES OVERNIGHT FRI...WEAK HIGH PRESSURE AND SUBSIDENCE SHOULD LEAD
TO SOME CLEARING TOWARD 12Z SAT.

FOR WINDS...A COLD FRONT IS MOVING EASTWARD ACROSS THE REGION...WITH
KRST ALREADY SHIFTED TO THE WEST AND KLSE SHOULD FOLLOW SUIT BY 06Z.
PRESSURE GRADIENT THEN TIGHTENS OVERNIGHT...WITH INCREASES EXPECTED
BEFORE 12Z. WINDS SHOULD STAY IN THE 14-18KT SUSTAINED RANGE...WITH
HIGHER GUSTS...FOR MUCH OF FRI.

&&

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

&&

$$

SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK


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