Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KARX 270821
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
321 AM CDT SUN JUL 27 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT SUN JUL 27 2014

LATEST WATER VAPOR SATELLITE IMAGERY INDICATING UPPER LEVEL CLOSED
LOW OVER NORTHERN MINNESOTA. LATEST MOSAIC RADAR SHOWING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ACROSS NORTHERN MINNESOTA IN
ASSOCIATION WITH PV ADVECTION WITH CLOSED UPPER LEVEL LOW PER LATEST
RAP.

MAIN CONCERN TODAY INTO THIS EVENING IS TIMING OF THE SHOWERS AND
ISOLATED THUNDERSTORMS INTO AND EXITING THE FORECAST AREA. THE
LATEST 27.00Z GFS/NAM CONTINUE TO SHOW STRONG PV ADVECTION AND DEEP
FORCING IN ASSOCIATION WITH THE CLOSED UPPER LEVEL LOW. THE
27.00Z GFS/NAM ARE IN GOOD AGREEMENT IN TIMING THE CLOSED LOW TO
MOVE SOUTH AND EAST OF THE FORECAST AREA AND THE VERTICAL MOTION
ASSOCIATED WITH THE CLOSED LOW BY 00Z MONDAY. TRENDED
PRECIPITATION CHANCES TO EXIT THE AREA BY 03Z MONDAY. THE 27.00Z
GFS/NAM SHOW WEAK ELEVATED INSTABILITY OVER THE FORECAST AREA AND
WILL CONTINUE MENTION THE POSSIBILITY OF THUNDERSTORMS.

SURFACE RIDGE BUILDS INTO WESTERN MINNESOTA AND THE
EASTERN DAKOTAS TONIGHT AND PROVIDE MOSTLY CLEAR SKIES AND A
DRIER AIRMASS ACROSS THE FORECAST AREA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 321 AM CDT SUN JUL 27 2014

MONDAY INTO TUESDAY...MAIN CONCERN IS THE POSSIBLE DIURNALLY DRIVEN
PRECIPITATION CHANCES. THE 27.00Z GFS/NAM DIG UPPER LEVEL TROUGH
OVER THE EASTERN UNITED STATES AND TRACK A COUPLE OF WEAK IMPULSES
EMBEDDED IN THE NORTHERLY FLOW ALOFT OVER PARTS OF THE FORECAST AREA.
BUFKIT SOUNDINGS SUGGEST MONDAY REMAINS DRY ACROSS THE AREA.
HOWEVER...BUFKIT SOUNDINGS SHOW STEEPER LOW LEVEL LAPSE RATES WITH
WEAK IMPULSE TRACKING INTO EASTERN WISCONSIN TUESDAY. ISOLATED
SHOWERS/THUNDERSTORMS WILL BE POSSIBLE MAINLY EAST OF THE
MISSISSIPPI RIVER...WITH SLIGHTLY HIGHER CHANCES OVER NORTH
CENTRAL WISCONSIN.

THE FORECAST AREA REGION REMAINS UNDER THE INFLUENCE OF THE UPPER
LEVEL TROUGH OVER THE EASTERN HALF OF THE UNITED STATES TUESDAY
NIGHT INTO SATURDAY. THE 27.00Z GFS/GEM/ECMWF CONTINUE TO SHOW
SEVERAL WEAK IMPULSES TO MOVE OVER THE AREA THROUGH THE PERIOD AND
POSSIBLY PRODUCE ISOLATED SHOWERS AND THUNDERSTORMS THROUGH MUCH
OF THE PERIOD. TEMPERATURES ARE EXPECTED TO REMAIN SLIGHTLY BELOW
NORMAL...AS THE 27.00Z GEFS INDICATE 850MB TEMPERATURE ANOMALIES
OF A HALF TO ONE DEGREE CELSIUS BELOW NORMAL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1240 AM CDT SUN JUL 27 2014

ISOLATED THUNDERSTORMS ARE CURRENTLY MOVING SOUTHEAST OUT THE
LA CROSSE AREA. SINCE THESE STORMS WILL BE OUT OF THE AREA
SHORTLY...DELAYED ISSUING THE KLSE TAF UNTIL 27.0540Z SO THAT
THERE WOULD BE NO THUNDERSTORMS IN IT. THESE THUNDERSTORMS ARE
BEING PRODUCED BY A TROUGH MOVING THROUGH THE REGION.

AS AN UPPER LEVEL LOW MOVES SOUTHEAST THROUGH THIS EVENING...
ANOTHER AREA OF SHOWERS AND ISOLATED STORMS WILL MOVE THROUGH THE
UPPER MISSISSIPPI RIVER VALLEY DURING THE AFTERNOON AND EARLY
EVENING. IN ADDITION TO THE PRECIPITATION...CEILINGS WILL BECOME
MVFR AND THE NORTHWEST WINDS WILL GUST INTO THE 20 TO 30 KNOT
RANGE.

AS SUBSIDENCE AND DRIER AIR MOVES INTO THE REGION IN THE WAKE OF
THE LOW...SKIES WILL QUICKLY CLEAR BETWEEN 28.00Z AND 28.03Z. IN
ADDITION THE SUSTAINED NORTHWEST WINDS WILL DROP TO LESS THAN
10 KNOTS.


&&

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

$$

SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...BOYNE



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.