Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 262103
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
403 PM CDT WED AUG 26 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 401 PM CDT WED AUG 26 2015

HIGH PRESSURE WAS CENTERED OVER THE TWIN CITIES AT MID AFTERNOON
ACCOMPANIED BY NEARLY CALM WINDS AND RELATIVE HUMIDITY IN THE 40 TO
45 PERCENT RANGE. THE HIGH WILL DRIFT SLOWLY EAST TONIGHT. THIS WILL
ALLOW FOR LOWS IN EASTERN MINNESOTA OUTSIDE THE METRO TO DROP INTO
THE LOWER 50S MIDDLE TO UPPER 40S IN WEST CENTRAL WISCONSIN. PATCHY
FOG IS FORECAST ONCE AGAIN FOR PORTIONS OF CENTRAL MINNESOTA AND
WEST CENTRAL WISCONSIN.

IN THE WAKE OF THE HIGH ON THURSDAY...SOUTHEAST SURFACE WINDS WILL
BEGIN TO INCREASE ACROSS THE AREA. LOW LEVEL MOISTURE TRANSPORT WILL
SPREAD INTO WEST CENTRAL AND SOUTHWEST MINNESOTA DURING THE
DAY...AHEAD OF A VIGOROUS LOW PRESSURE SYSTEM MOVING INTO THE
CENTRAL PLAINS. WEST CENTRAL AND SOUTHWEST MINNESOTA WILL ALSO SEE
INCREASING INSTABILITY DEVELOPING DURING THE DAY AS WELL. THE
SITUATION IS SIMILAR TO THIS MORNING WHEN A SMALL BAND OF
THUNDERSTORMS DEVELOPED NEAR KABR AND DROPPED SOUTHEAST THROUGH THE
MORNING AND EARLY AFTERNOON HOURS. THE ONE DIFFERENCE IS THAT MID
LEVEL FLOW WILL BE MORE ANTICYCLONIC ON THURSDAY DUE TO THE STORM
SYSTEM ARRIVING FROM THE WEST...WHERE AS THIS MORNING WE HAD A WEAK
SHORT WAVE MOVING SOUTHEAST ACROSS EASTERN SOUTH DAKOTA. NEEDLESS TO
SAY...MOST CAMS ARE SHOWING SOME SHOWER AND THUNDERSTORM ACTIVITY
PUSHING IN FROM EASTERN SOUTH DAKOTA FROM LATE MORNING ONWARD WITH
THE MOST CONCENTRATED ACTIVITY IN THE AFTERNOON ACROSS SOUTHWEST AND
SOUTH CENTRAL MN NEAR THE I-90 CORRIDOR.

AT THIS POINT...PUSHED CHANCE TO LIKELY POPS ACROSS THE
AFOREMENTIONED AREAS DURING THE AFTERNOON. THE ONE CONCERN IS THAT
IT MAY COME QUICKER AND HIGHER POPS MAY BE NEEDED SOONER (THURSDAY
MORNING). HIGH TEMPERATURES WILL LIKELY BE HELD TO THE LOWER 70S
ACROSS FAR SOUTHERN MN ON THURSDAY WITH MIDDLE TO UPPER 70S TO THE
NORTH AND EAST.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 401 PM CDT WED AUG 26 2015

TWO THINGS CAN BE SAID ABOUT THE LONG TERM. ONE...MODELS ARE
BEGINNING TO HONE IN ON A SOLUTION FOR THE TRACK OF A HEAVY RAIN
EVENT THU NIGHT/FRIDAY ALONG THE I-90 CORRIDOR. TWO...AFTER A TASTE
OF FALL THIS WEEK...A SIGNIFICANT PATTERN SHIFT WILL BRING SUMMER
LIKE WEATHER BACK NEXT WEEK.

THE WAVE OF INTEREST FOR THU NIGHT/FRIDAY IS NOW MOVING ACROSS UTAH
AND WILL CONTINUE TO ROUND THE UPPER RIDGE CENTERED OVER
NM/CO...EVENTUALLY MOVING ALONG THE MN/IA BORDER FRIDAY. WITH THE
12Z MODEL RUNS...WE HAVE SEEN MODELS START TO HONE IN ON PRODUCING
THE HEAVIEST PRECIP ALONG THE I-90 CORRIDOR...LIKELY IN THE FORM OF
2-3 INCHES OF RAIN. THOUGH THIS AMOUNT SEEMS A BIT EXCESSIVE
CONSIDERING THE FACT THAT INSTABILITY AND THEREFORE CONVECTION WILL
BE LACKING...THIS WAVE WILL BE JUICED...WITH PWATS PUSHING
1.75"...WHICH IS NEAR THE CLIMATOLOGICAL MAX FOR STC/MPX FOR THE END
OF AUGUST. IN ADDITION...IT/S NOT JUST H85 MOISTURE TRANSPORT THAT
IS STRONG...BUT SW MID LEVEL JET IN EXCESS OF 40 KTS OUT AHEAD OF
THE WAVE WILL ENSURE DEEP MOISTURE TRANSPORT AT THE NOSE OF THE LOW
LEVEL AND MID LEVEL JETS...AIDING IN THE HIGHER PRECIP AMOUNTS
EXPECTED. THERE WILL BE A TIGHT GRADIENT IN QPF AS WELL...WITH VERY
LITTLE PRECIP EXPECTED ACROSS CENTRAL MN. FOR QPF...STUCK CLOSE TO
WHAT WPC HAS...WHICH IS A GOOD BLEND BETWEEN THE GFS/ECMWF.

FOR CHANGES MADE TO THE GOING FORECAST THU NIGHT/FRIDAY...KEPT THE
NRN EDGE OF MENTIONABLE PRECIP UNCHANGED...BUT DRAGGED THE LIKELY
AND HIGHER POPS QUITE A BIT FARTHER NORTH...WITH MODEL AGREEMENT
PRETTY GOOD IN SPREADING PRECIP UP THROUGH WILLMAR...ACROSS THE TWIN
CITIES AND TOWARD LADYSMITH. ALSO SLOWED POPS A BIT ACROSS THE AREA
FRIDAY INTO FRIDAY EVENING AS THE 12Z ECMWF SLOWED THE PROGRESSION
OF THE SYSTEM A BIT. LOOKS VERY LIKELY THAT FRIDAY MAY PRETTY MUCH
BE A WASHOUT ACROSS MUCH OF SOUTH CENTRAL INTO EAST CENTRAL MN.

BEHIND THIS SYSTEM...THE GFS/ECMWF CONTINUE TO BE IN GOOD AGREEMENT
WITH H5 HEIGHTS RAPIDLY BUILDING ACROSS THE AREA ON SATURDAY AS A
DEEP THROUGH DIGS INTO THE PAC NW AND RIDGING BEGINS TO BUILD UP
INTO THE GREAT LAKES. BY SUNDAY...THE ECMWF SHOWS H85 TEMPS BUILDING
TO A FEW DEGREES ON EITHER SIDE OF 24C...WHICH REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. THESE SORT OF H85 TEMPERATURES
WILL SUPPORT HIGHS IN THE MID/UPPER 80S ALL OF NEXT WEEK...WITH A
FEW 90S NOT OUT OF THE QUESTION EITHER...ESPECIALLY IN WRN MN. WE
STILL HAVE A SMALL MENTION FOR PRECIP TUE/WED IN RELATION TO A FRONT
THAT WILL BE WASHING OUT ACROSS THE AREA. HOWEVER...WITH THE RIDGE
OVERHEAD...WE LOOK TO REMAIN CAPPED NEXT WEEK...SO DOUBT THIS WASHED
OUT FRONT WILL DO MUCH OF ANYTHING. IN FACT...THE GFS/ECMWF DO NOT
SHOW MUCH OF A CHANCE FOR PRECIP UNTIL LABOR DAY WEEKEND WITH THE
UPPER RIDGE REMAINING IN CONTROL NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1220 PM CDT WED AUG 26 2015

A FEW SHOWERS AND STORMS WILL CONTINUE TO DIMINISH EARLY THIS
AFTERNOON ACROSS FAR SW MN...AND RWF COULD CONTINUE TO SEE SOME
SCATTERED MID-HIGH LEVEL CLOUDS BUT WILL REMAIN AT VFR. EXPECT ALL
TERMINALS TO HAVE VFR CONDITIONS PERSIST THROUGH LATE
TONIGHT...THOUGH WINDS GOING CALM UNDER CLEAR SKIES IN WESTERN WI
WILL LEAD TO ANOTHER GOOD RADIATIONAL COOLING SETUP OVERNIGHT.
THEREFORE...PATCHY FOG IS POSSIBLE BETWEEN 08-13Z AT EAU AND RNH.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH THE END OF THE
PERIOD.

KMSP...LIGHT WINDS AND CLEAR SKIES WILL CONTINUE THROUGH
TONIGHT...AND ONLY SOME SCATTERED MID-HIGH LEVEL CLOUDS ARE
EXPECTED THURSDAY. WINDS WILL PICK UP SLIGHTLY AND BECOME
SOUTHERLY...GUSTING BETWEEN 10-15 KTS THURSDAY AFTERNOON.

/OUTLOOK FOR KMSP/
THU NIGHT...VFR. CHC MVFR SHRA/TSRA. WIND S 10 KTS.
FRI...VFR. CHC SHRA/TSRA WITH MVFR POSSIBLE. WINDS SE 5-10 KTS.
SAT...VFR. WINDS SE 5-10 KTS.


&&

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

$$

SHORT TERM...RAH
LONG TERM...MPG
AVIATION...ADL


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