Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 270509
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1209 AM CDT SAT SEP 27 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 358 PM CDT FRI SEP 26 2014

SHORT TERM CONCERNS ARE THE MOVEMENT OF THE IOWA UPPER LOW AND
THREAT OF ISOLATED SHOWERS/THUNDER INTO SATURDAY AFTERNOON.

SOME CLOUD COVER EXPECTED ACROSS THE CWA OVERNIGHT AS WEAK 85H WAA
CONTINUES TO LIFT OVER THE AREA. LOW LEVEL SOUTHEAST FLOW EXPECTED
TO CONTINUE AS PRESSURE GRADIENT BEGINS TO INCREASE...ESPECIALLY TO
THE WEST.  STILL COULD SEE BOUNDARY LAYER DECOUPLE TO THE FAR
EAST...IN CLOSE PROXIMITY TO THE RETREATING SURFACE HIGH.  OVERNIGHT
LOWS SHOULD REMAIN WARMER THAN LAST NIGHT.

UPPER LEVEL CIRCULATION IS FORECAST TO LIFT NORTHEAST AFFECTING
MAINLY THE EASTERN PORTION OF THE CWA SATURDAY AFTERNOON.
INSTABILITY INCREASES DURING THE AFTERNOON...WITH MLCAPE INCREASING
TO 1000-1500 J/KG OVER SOUTH CENTRAL MN FOR THE AFTERNOON.  WILL
MENTION ISOLATED THUNDER THIS AREA. MEAGER FORCING HOWEVER SHOULD
LIMIT OVERALL DEVELOPMENT.  VARIOUS CAMS CONTINUE TO SHOW SOME
ECHOES DEVELOPING DURING PEAK HEATING. SMALL POPS REMAIN WARRANTED
FOR NOW. TEMPERATURES ARE EXPECTED TO WARM THROUGH THE UPPER 70S AND
LOWER 80S ONCE AGAIN DURING THE AFTERNOON.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 358 PM CDT FRI SEP 26 2014

THE PRIMARY CONCERNS IN THE LONG TERM PORTION OF THE FORECAST
RELATE TO PRECIPITATION CHANCES WITH AN ACTIVE PATTERN UNFOLDING.

SATURDAY NIGHT AND SUNDAY LOOK TO BE FAIRLY BENIGN WEATHER-WISE AS
THE AREA REMAINS SANDWICHED BETWEEN THE DEPARTING SURFACE RIDGE
AND AN APPROACHING TROUGH TO THE NORTH. TEMPERATURES WILL REMAIN
ABOVE NORMAL...WITH LOWS IN THE MID/UPPER 50S AND HIGHS FROM 75 TO
80 DEGREES.

ON MONDAY THE AFOREMENTIONED FRONT SAGS INTO CENTRAL MN AND WEST
CENTRAL WI. FORCING AND LAYER MOISTURE APPEAR JUST SUFFICIENT TO
WARRANT 20-30 POPS NORTH AND EAST OF THE INTERSTATE 94
CORRIDOR...JUST SCRAPING THE TWIN CITIES ON THE SOUTHERN/WESTERN
EDGE.

THE MONDAY NIGHT INTO TUESDAY TIME FRAME LOOKS TO PROVIDE A BRIEF
RESPITE FROM PRECIPITATION AS RIDGING PREVAILS LOCALLY.

TUESDAY BRINGS THE ARRIVAL OF A NEARLY STACKED SYSTEM TO THE
DAKOTAS AND NORTHWESTERN MN. WHILE AMPLITUDE DIFFERENCES BETWEEN
THE 26.12Z GFS AND ECMWF ARE QUITE APPARENT...BOTH MODELS FEATURE
A BAND OF DECENT FORCING AND LAYER MOISTURE WISPING ACROSS THE
AREA ON TUESDAY AFTERNOON/NIGHT. HAVE INCLUDED HIGH CHANCE POPS
FOR LATE TUESDAY INTO EARLY WEDNESDAY.

FORECAST CONFIDENCE DECREASES NOTABLY FOR WEDNESDAY AND
THURSDAY...WITH SIGNIFICANT DIFFERENCES BETWEEN THE GFS AND ECMWF
REGARDING THE EVOLUTION OF THE WESTERN CONUS TROUGH STILL
NOTED...PARTICULARLY WITH REGARD TO HOW NORTHERN AND SOUTHERN
STREAMS PHASE. HAVE INCLUDED LOW CHANCE POPS FOR THE REMAINDER OF
NEXT WEEK UNTIL REFINEMENT CAN HAPPEN WITH FUTURE MODEL RUNS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1159 PM CDT FRI SEP 26 2014

UPPER LOW OVER IA WILL CONTINUE TO SLOWLY DRIFT NORTH THROUGH THE
NIGHT...KEEPING A STEADY STREAM OF 5K-7K FT CLOUDS HEADING OUR
DIRECTION. MAY SEE ISOLATED SHOWERS DEVELOP BETWEEN 12 AND 15Z IN
SOUTH CENTRAL MN...SPREADING NORTH AND EAST INTO THE AFTERNOON.
HOWEVER...COVERAGE WITH ANYTHING WE DO SEE LOOKS TO BE WAY BELOW A
LEVEL WHERE THEY WOULD BECOME WORTH MENTIONING IN SOME WAY IN THE
TAFS. NOT MUCH LOOKS TO CHANGE WITH THE PRESSURE GRADIENT
SATURDAY...SO LOOK FOR WINDS TO BEHAVE VERY SIMILAR TO WHAT WAS
SEEN FRIDAY. ON THE FENCE ABOUT KEEPING MVFR VIS RESTRICTION THIS
MORNING AT EAU GIVEN CLOUD COVER FLOATING AROUND. AT THIS
POINT...DELAYED ITS ARRIVAL BY A COUPLE OF HOURS...BUT MAY JUST
NEED TO REMOVE COMPLETELY BY 9Z.

KMSP...NO ISSUES EXPECTED THIS PERIOD AS UPPER LOW OVER IOWA WILL
JUST SUPPLY US WITH VARYING AMOUNTS OF CLOUDS BETWEEN 5K AND 7K
FT. CONFIDENCE IN LOW COVERAGE SHRA TODAY IS VERY LOW...SO STILL
FEEL CONFIDENT IN GOING WITH A DRY FORECAST.

/OUTLOOK FOR KMSP/
SUN...VFR. WINDS S 10KTS.
MON...VFR. WINDS NE 5 KTS.
TUE...VFR. CHANCE MVFR/SHRA OVERNIGHT. WINDS SE 10 KTS.

&&

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

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...MPG





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