Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 012020
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
320 PM CDT FRI AUG 1 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 305 PM CDT FRI AUG 1 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL COME TO AN END THIS EVE
WITH THE LOSS OF DAYTIME HEATING. CLOUDS SCATTER OUT TONIGHT AND
WINDS BECOME LIGHT AND VARIABLE...WHICH MAY SET THE STAGE FOR
PATCHY FOG DEVELOPMENT OVERNIGHT...PARTICULARLY IN AREAS THAT
RECEIVE EVENING RAINFALL FROM CENTRAL MN INTO WEST CENTRAL WI.

SATURDAY BRINGS THE RETURN TO SOUTHERLY FLOW AHEAD OF A NORTHERN
PLAINS TROUGH. H85 TEMPS MODERATE TO BETWEEN +16 AND +18C ACROSS MN.
SHOULD EASILY ACHIEVE MID 80S...WITH SOME UPPER 80S POSSIBLE OVER
WEST CENTRAL MN. LOWER 80S WILL BE COMMON ACROSS WI. THE AFTERNOON
WILL BECOME MORE SKETCHY AS FAR AS BEING ABLE TO CONFIDENTLY
FORECAST DRY WEATHER...ESPECIALLY FROM WEST CENTRAL WI INTO
SOUTHEASTERN MN...WHERE SEVERAL MODELS INDICATE A POCKET OF
INSTABILITY /PER CAPES INCREASING TO OVER 1500 J/KG/. THERE ISN/T
ANY FORCING MECHANISM TO HANG OUR HATS ON...BUT INSTABILITY COULD
PROVE SUFFICIENT ENOUGH TO GENERATE ISOLATED THUNDERSTORMS GENERALLY
ALONG/EAST OF INTERSTATE 35.

THE OTHER AREA TO MONITOR SATURDAY AFTERNOON WILL BE WEST CENTRAL
MN...AS THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH
SAGS INTO MINNESOTA. WHILE THE MAIN FORCING WILL BE DISPLACED WELL
NORTH OF THE AREA...COULD SEE A FEW ISOLATED STORMS SNEAK INTO THE
NORTHWESTERN CWA /NEAR ALEXANDRIA/ DURING THE LATE AFTERNOON HOURS.
CERTAINLY A HIGHER PROBABILITY AS WE HEAD INTO SATURDAY NIGHT
HOWEVER.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 305 PM CDT FRI AUG 1 2014

THE MAIN CHG IN THE EXTENDED PERIOD IS TO LOWER POPS BY
MIDWEEK...ESPECIALLY ACROSS CENTRAL MN DUE TO THE CONTINUED
SOUTHERLY TREND OF THE FRONTAL BOUNDARY AND MEAN UPPER AIR FLOW
FROM THE NW.

THE FRONTAL BOUNDARY THAT IS EXPECTED TO SLOWLY MOVE SOUTHEAST
ACROSS THE UPPER MIDWEST BY THE LADDER PART OF THE WEEKEND SHOULD
CONTINUE LOW END CHC POPS...ESPECIALLY ACROSS EC MN/WC WI DUE TO
BETTER MOISTURE POOLING AND UPPER LEVEL FORCING. HOWEVER...AFTER
SUNDAY NIGHT THIS FRONT MAY BE FAR ENOUGH SOUTH TO PRECLUDE
ANYTHING SIGNIFICANT...ESPECIALLY IN TERMS OF HEAVIER RAINFALL
POTENTIAL AS PREVIOUSLY FORECAST HAD. THIS IS BASED ON THE
STRONGER LONG WAVE TROUGH ACROSS THE EASTERN HALF OF NORTH AMERICA
WHICH WILL LEAD TO A MORE NW FLOW IN THE UPPER MIDWEST. AT THE
SFC...HIGH PRESSURE IS EXPECTED TO DOMINATE WITH THE BEST THERMAL
BOUNDARY SW OF MPX CWA.

THERE REMAINS SOME UNCERTAINTY...ESPECIALLY IN TERMS OF THE
STRENGTH OF THE LONG WAVE TROUGH AND THE EC HOLDING ONTO THE
HIGHER POPS WED. HOWEVER...AM NOT CONFIDENT ON ANY LONG DURATION
RAINFALL EVENT UNTIL THE UPPER FLOW CHGS...AND THE HIGHER PWAT
VALUES AND ASSOCIATED DISTURBANCE ACROSS BAJA CALIFORNIA...MOVES
OVER THE UPPER RIDGE FORECAST TO HOLD ARND NEW MEXICO/COLORADO AND
TEXAS REGION THROUGH THE END OF NEXT WEEK.

IN ADDITION TO THE LOWER POPS AND THE FRONT FURTHER TO THE S/SW OF
MPX CWA...THICKNESS VALUES ALLOW FOR A COOLER THAN NORMAL WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1208 PM CDT FRI AUG 1 2014

THE CUMULUS DECK WILL BECOME MORE EXTENSIVE THIS AFTERNOON...WITH
SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP GENERALLY
ALONG/NORTH OF INTERSTATE 94 FROM CENTRAL MN INTO WEST CENTRAL WI.
THE MOST-AFFECTED SITES WILL BE KSTC-KRNH-KEAU...WITH KMSP AND
KAXN BEING ON THE SOUTHERN/WESTERN FRINGES OF THE ACTIVITY. HAVE
MAINTAINED TEMPOS AT WI SITES...AND VC MENTIONS AT MN SITES /WITH
THE EXCEPTION OF KEEPING KRWF DRY/. SKIES CLEAR THIS EVE AND WINDS
DECREASE TO AOB 5 KTS...WITH BR POSSIBLE AT WEST CENTRAL WI
SITES...ESPECIALLY WHERE PRECIP OCCURS. HAVE INCLUDED MVFR/IFR VSBY
RESTRICTIONS AT KRNH/KEAU...BUT THAT COULD BE EVENTUALLY LOWERED
TO LIFR. SCT-BKN MID LEVEL CLOUDS ARE EXPECTED AGAIN
SATURDAY...WITH WINDS VEERING TO SOUTH-SOUTHWEST AS A TROUGH NOSES
INTO WEST CENTRAL MN.

KMSP...
KMSP IS EXPECTED TO BE ON THE SRN/WRN FRINGES OF THE MAIN AREA OF
SHRA/TS THIS AFTERNOON...SO HAVE HELD ONTO THE VCTS MENTION VERSUS INCLUDING
A TEMPO AT THIS POINT. CUMULUS CLOUDS CLEAR OUT THIS EVE AND
NORTHWEST WINDS DECLINE BELOW 5 KTS AND GRADUALLY VEER TO
SOUTHERLY IN DIRECTION. BKN MID CLOUDS EXPECTED AGAIN BY LATE
MORNING.

/OUTLOOK FOR KMSP/
SAT NIGHT...VFR. SLIGHT CHANCE TSRA. WINDS VARIABLE 5 KTS.
SUN...VFR. SLIGHT CHANCE TSRA. WINDS SW 5-10 KTS.
MON...VFR. CHANCE TSRA. WINDS ESE 5-10 KTS.
TUE...VFR. CHANCE MVFR IN TSRA. WINDS EAST 5-7KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...LS
LONG TERM...JLT
AVIATION...LS



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