Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 230057
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
757 PM CDT FRI AUG 22 2014

.UPDATE...
ISSUED AT 727 PM CDT FRI AUG 22 2014

UPDATED TO INCLUDE 00Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 350 PM CDT FRI AUG 22 2014

INITIAL SHORT TERM CONCERN IS THE REDEVELOPMENT AND COVERAGE OF
FOG LATER TONIGHT. CLOUD DECK REMAINS TRAPPED UNDER STRONG
INVERSION OVER EASTERN MN/NORTHWEST WISCONSIN. EXPECT MUCH OF THIS
AREA OF THICKER CLOUD COVER TO DISSIPATE/ERODE FURTHER ALONG THE
ITS OUTERMOST PERIPHERY. HOWEVER...LOOKS LIKE A SMALL AREA OF
CLOUD COVER WILL REMAIN TO THE NORTHEAST. GIVEN THE LATE BREAK UP
OF CLOUDS AND COOLER TEMPERATURES...COULD SEE FOG DEVELOP AGAIN
BEFORE MIDNIGHT IN THE EAST. WINDS ARE EXPECTED TO REMAIN
LIGHT...SO STRATUS AND FOG IS ONCE AGAIN ANTICIPATED OVER THE
NORTHEAST PORTION OF THE CWA. FURTHER SOUTHWEST...HIGH CLOUDS WILL
MOVE IN LATER TONIGHT...AND THIS MAY HELP PRECLUDE DENSE FOG FROM
FORMING. WILL HAVE TO MONITOR INTO THE EVENING. TEMPERATURES
SHOULD COOL BACK TO MAINLY THE MID/UPPER 60S.

LATER TONIGHT...MODELS HAVE TRENDED SLOWER WITH THE FORCING MOVING
IN. WILL MAINTAIN A SMALL CHANCE TO THE SOUTHWEST FOR NOW. THE
MAIN FORCING MOVES LONG THE DAKOTAS/MN BORDER LATE
MORNING/AFTERNOON. WE STILL MAY SEE A BAND OF WAA SHOWERS/ISOLATED
THUNDER LIFT NORTHEAST ACROSS EASTERN MN...MAINLY SATURDAY
AFTERNOON. THE MAIN SHOW SHOULD HOLD OFF UNTIL THE COMING EVENING.
SEVERE WEATHER POTENTIAL INCREASES DURING THE DAY AS WELL WITH
OVERALL DEEP LAYER SHEAR INCREASING AHEAD OF THE MAIN TROUGH LATE
SATURDAY AFTERNOON OVER THE WEST. LARGE HAIL/DAMAGING WINDS
POSSIBLE OVER THE WEST AS THE WARM FRONT LIFTS NORTHEAST TOWARD
SOUTHWEST MN LATER IN THE AFTERNOON.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 350 PM CDT FRI AUG 22 2014

THE LONGER RANGE OF THE FORECAST LOOKS TO BE MARKED BY OCCASIONAL
SHOWER AND THUNDERSTORM CHANCES OVER THE WEEKEND...HOT
TEMPERATURES SUNDAY...THEN COOL AND DRY WEATHER FOR MUCH OF THE
UPCOMING WEEK.

AT THE START OF THE LONG TERM FORECAST PERIOD...A SURFACE LOW
CIRCA 1000MB IS PROGGED TO BE LOCATED OVER THE DAKOTAS. MODEL
SOLUTIONS ALL FEATURE THIS SYSTEM...ALTHOUGH AMPLITUDE AND SPATIAL
DIFFERENCES ARE QUITE APPARENT. THIS LEADS TO LOW CONFIDENCE WITH
HOW FAR EAST THE SHOWERS AND THUNDERSTORMS WILL REACH ON SATURDAY
NIGHT...BUT MUCH HIGHER CONFIDENCE THAT WEST CENTRAL MINNESOTA
WILL EXPERIENCE CONVECTION /IN CLOSER PROXIMITY TO THE LOW AND
FORCING/ADVECTION/.

ON SUNDAY...THE LOW LIFTS TO MANITOBA/ONTARIO...WHILE THE
ASSOCIATED COLD FRONT PASSES ACROSS THE AREA. AHEAD OF THE
FRONT...THE THERMAL RIDGE NOSES INTO EAST CENTRAL MINNESOTA AND
WEST CENTRAL WISCONSIN. EXPECT HIGHS TO SNEAK INTO THE LOWER
90S...WHICH MEANS A HEAT ADVISORY COULD BE NEEDED FOR A PORTION
OF THE AREA...POTENTIALLY INCLUDING HENNEPIN AND RAMSEY COUNTIES.
SCATTERED SHOWERS AND THUNDERSTORMS WILL REMAIN A POSSIBILITY FOR
MUCH OF THE AREA ON SUNDAY...SO WILL HAVE TO MONITOR HOW RESIDUAL
CLOUDS/PRECIPITATION IMPACT HIGH TEMPS.

FOR MONDAY...AN OVERALL DRY DAY IS EXPECTED AS WEAK
RIDGING/SUBSIDENCE WORKS INTO THE AREA. THE BREAK IN PRECIPITATION
WILL BE SHORT LIVED HOWEVER...AS AN INVERTED TROUGH NOSES INTO
THE UPPER MIDWEST ON MONDAY NIGHT. MODELS ARE NOT IN GREAT
AGREEMENT WITH THIS SYSTEM EITHER...BUT THERE IS RATHER HIGH
CONFIDENCE THAT SHOWERS AND THUNDERSTORMS WILL BLOSSOM FROM
SOUTHERN MN ACROSS EAST CENTRAL MINNESOTA AND WEST CENTRAL
WISCONSIN ON MONDAY EVENING. THE BOUNDARY THEN SAGS JUST SOUTH OF
THE AREA THROUGH THE MIDDLE OF THE WEEK...AND FOSTERS SHOWER AND
THUNDERSTORM CHANCES THROUGH WEDNESDAY...ESPECIALLY ACROSS
SOUTHERN MINNESOTA. THE LOCATION WHERE THE FRONT STALLS IS STILL
UNCERTAIN...BUT HEAVY RAINFALL COULD BECOME A CONCERN WITH THE
POTENTIAL FOR MULTIPLE ROUNDS OF PRECIPITATION TO POTENTIALLY
TRACK OVER THE SAME AREA.

TEMPERATURES WILL BE NOTABLY COOLER FROM TUESDAY THROUGH
THURSDAY...WITH HIGHS IN THE UPPER 60S TO MID 70S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 727 PM CDT FRI AUG 22 2014

VISIBLE SATELLITE SHOWS A STOIC SWATH OF LOW STRATUS NEAR AND NE
OF KMSP...COVERING KRNH AND KEEPING IT WITHIN LOWER MVFR RANGE.
KMSP IS WITHIN UPPER MVFR RANGE AND IS LIKELY TO REMAIN THERE
UNTIL THE CLOUDS SCATTER OUT. THE REMAINING TAF SITES DO HAVE
VARIED LEVELS OF VFR CLOUDS. BY LATE EVENING...THE PLENTIFUL LOW
LEVEL MOISTURE AND LIGHT WINDS WILL AGAIN COMBINE TO PRODUCE IFR-
OR-LOWER CONDITIONS...MAINLY DUE TO CEILINGS BUT ALSO POTENTIALLY
FOG FOR THE USUAL SUSPECTS /A.K.A. KSTC...KRNH AND KEAU/. HAVE
MAINTAINED THIS THINKING IN THE 00Z TAFS WITH THE WORST CONDITIONS
MAINLY BETWEEN 08Z-14Z SAT. CONDS THEN LOOK TO SLOWLY IMPROVE THRU
THE MRNG HOURS. ONE OTHER COMPLICATION IS THE POTENTIAL
DEVELOPMENT OF SCATTERED TO NUMEROUS SHOWERS/TSTMS OVER ERN SD/ERN
NE/WRN IA THAT WILL SPREAD INTO SWRN MN BY AROUND DAYBREAK THRU
LATE MRNG. THIS WOULD AFFECT KRWF-KAXN-KSTC LATE MRNG INTO THE
EARLY AFTN. TOO EARLY ATTM TO DETERMINE FLIGHT COND DETERIORATION
BUT WILL FOR NOW SHOW PREVAILING PRECIP AT THE WRN TAF SITES.

KMSP...MVFR CONDS LOOK TO HOLD FOR MUCH OF THE EVENING...
INCLUDING DROPPING TO SUB-1700 FT CEILINGS LATER THIS THIS EVENING
AND HOLDING THERE THRU THE EARLY MRNG HRS. THERE MAY BE SOME
BREAKS BUT WITH DECOUPLING THIS EVENING WITH PLENTY OF LOW LEVEL
MOISTURE...AM HAVING A HARD TIME SEEING KMSP BREAKING AWAY FROM
CLOUD COVER. IFR CONDS THEN SETTLE IN CLOSE TO DAYBREAK BUT AM NOT
XPCTG MUCH OF A VSBY RESTRICTION FROM VFR...JUST INTO MVFR. THE
IFR CIGS WILL THEN LIKELY LAST THRU LATE MRNG TO AROUND
MIDDAY...THEN A SLOW IMPROVEMENT IS EXPECTED TMRW AFTN.

/OUTLOOK FOR KMSP/
SUN...VFR. MVFR/TSRA POSSIBLE EVENING/OVERNIGHT. WINDS S10G20 KTS.
MON...VFR. WINDS W 5-10 KTS.
TUE...MAINLY VFR. CHC MVFR IN TSRA. WINDS NE 5-10 KTS.

&&

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

$$

UPDATE...JPC
SHORT TERM...DWE
LONG TERM...LS
AVIATION...JPC






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