Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 140432
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1132 PM CDT SUN JUL 13 2014

.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 200 PM CDT SUN JUL 13 2014

STRONG PUSH OF ABNORMALLY COLD AIR MOVES IN FOR MONDAY AND
TUESDAY...WITH 850 MB TEMP ANOMALIES VIA THE SREF OF -2 TO -3. 850
MB TEMPS FLIRT WITH +4 C ON MONDAY. SHOULD BE QUITE CHILLY FOR MID
JULY...WITH HIGHS MORE REMINISCENT OF LATE APRIL/EARLY MAY. A FEW
RECORD COLD HIGH TEMPS ARE LIKELY AT SOME LOCATIONS.

THE COLD AIR IS FINDING THE REGION THANKS TO AN UPPER LEVEL
TROUGH...WHICH WILL HOLD ACROSS THE GREAT LAKES THROUGH TUE...THEN
EASE EAST FOR THE LATER PART OF THE WORK WEEK. BITS OF ENERGY WILL
SLIDE THROUGH THE FLOW...WITH THE STRONGEST PIECE SLATED TO SPIN
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY AROUND 18Z MON. ANOTHER
RIPPLE SHOULD MOVE THROUGH TUE AFTERNOON. NAM/GFS DEVELOP ABOUT 500
J/KG OF SBCAPE MON/TUE AFTERNOON...WITH BUFKIT SOUNDINGS POINTING TO
A SKINNY/SHORT LAYER OF INSTABILITY. DECENT 1000-850MB LAPSE RATES.
ENOUGH LIFT TO FAVOR MOSTLY AFTERNOON SHOWER CHANCES...GENERALLY
EAST OF THE MISSISSIPPI ON MON. TUE CHANCES A BIT LESS THANKS TO A
WEAKER SHORTWAVE.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 200 PM CDT SUN JUL 13 2014

GFS/ECMWF TRENDING TOWARD A GRADUAL SHIFT TO A MORE ZONAL UPPER
LEVEL PATTERN FOR THE REST OF THE WEEK...AND EXPECT TEMPS TO WARM
BACK TO MID JULY NORMALS FOR NEXT WEEKEND.

WITH THE REGION STILL UNDER SOME CYCLONIC FLOW A LOFT
WED/THU...CAN/T RULE OUT A THREAT FOR SOME SHOWERS IF A BIT OF
ENERGY CAN SWING THROUGH THE TROUGH. GFS SUGGESTS THIS WHILE THE EC
STAYS DRY. BOTH HAVE WEAK HIGH PRESSURE AT THE SFC. WILL LIKELY STAY
WITH A DRY FORECAST UNTIL A CLEARER/MORE DEFINED SIGNAL FAVORS A
SHOT FOR SHOWERS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1132 PM CDT SUN JUL 13 2014

UPPER LEVEL LOW CURRENTLY OVER SOUTHWEST ONTARIO WILL CONTINUE TO
MOVE SOUTH/SOUTHEAST THROUGH MONDAY AND IS EXPECTED TO SLIDE
ACROSS LAKE SUPERIOR AND THE U.P. OF MICHIGAN. A STRONG SHORT WAVE
TROUGH WILL ROTATE AROUND THE UPPER LEVEL LOW AND COME ACROSS THE
AREA DURING THE DAY. AT THE SAME TIME...THE COLD AIR ALOFT WILL
ROTATE THROUGH WITH THE 14.00Z NAM SHOWING 500 MB TEMPERATURES
AROUND -20C. THIS WILL HELP TO SET UP GOOD LAPSE RATES WITH 7C/KM
UP THROUGH 650 MB EXPECTED DURING THE AFTERNOON. THESE LAPSE RATES
COMBINED WITH THE FORCING FROM THE SHORT WAVE TROUGH WILL PRODUCE
SOME SHOWERS AND WILL HOLD ONTO THE VCSH FOR BOTH SITES FROM LATE
MORNING INTO THE EARLY EVENING. EXPECTING PRIMARILY VFR
CEILINGS...BUT MVFR NOT OUT OF THE QUESTION IF A HEAVIER SHOWER
MOVES THROUGH...BUT CONFIDENCE ON THIS HAPPENING AND THE TIMING IS
TOO LOW TO INCLUDE IN THE FORECAST. THE LAPSE RATES WILL ALSO
PROVIDE A WELL MIXED BOUNDARY LAYER THAT SHOULD ALLOW GUSTY
NORTHWEST WINDS TO DEVELOP. WITH THE LOSS OF DAYTIME
HEATING...WILL SHOW THE SHOWERS AND GUSTS DISSIPATING BY MID
EVENING...BUT PLAN TO HOLD ONTO THE CEILINGS AS SATELLITE IMAGERY
SHOWING PLENTY OF CLOUDS CURRENTLY ON THE WEST AND NORTHWEST SIDE
OF THE UPPER LEVEL LOW.

&&

.CLIMATE...
ISSUED AT 259 AM CDT SUN JUL 13 2014

RECORD COOL HIGH TEMPERATURES ARE POSSIBLE MONDAY AND TUESDAY AS AN
UNSEASONABLY COLD AIRMASS SETTLES OVER THE UPPER MISSISSIPPI RIVER
VALLEY.

FOR LA CROSSE...
MONDAY....FORECAST HIGH 68.  RECORD 65 IN 1994
TUESDAY...FORECAST HIGH 70.  RECORD 68 IN 1962

FOR ROCHESTER...
MONDAY....FORECAST HIGH 64.  RECORD 64 IN 1952
TUESDAY...FORECAST HIGH 67. RECORD 67 IN 1962

&&

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

$$

SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
CLIMATE......AJ



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