National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KMPX 111751
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1251 PM CDT SAT MAY 11 2013

.UPDATE...

18Z AVIATION DISCUSSION ADDED BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CDT SAT MAY 11 2013

MAIN ISSUES ARE STRONG WIND TODAY AND FROST POTENTIAL TONIGHT. WINDS
GUSTING OVER 30 KNOTS FOR A SHORT TIME IN THE WAKE OF FRONT BUT
SECONDARY SURGE IS NOT FAR BEHIND...EVIDENT IN OBS AND SHORT TERM
MODELS. EXCELLENT SUBSIDENCE AS WELL...AND MOST PROFILES VIEWED IN
BUFKIT INDICATE ADIABATIC LAPSE RATES THROUGH ABOUT 7K FEET WITH
GUSTS 30-35 KNOTS. HAVE MAINTAINED FORECAST OF GUSTS AROUND 30
KNOTS OVER MOST AREAS TODAY BUT WOULD NOT BE SURPRISED TO SEE SOME
35 KNOT GUSTS...ESPECIALLY IN WESTERN AND SOUTHERN MN.

WINDS TAPER OFF TONIGHT BUT GRADIENT IS SUCH THAT 5-10 KNOTS WILL
PERSIST OVER EASTERN MN AND WISC. THIS SHOULD KEEP TEMPS AROUND 32
TONIGHT WITH WIND PRECLUDING MUCH FROST. WESTERN COUNTIES SHOULD
DROP TO 3-5 KNOTS LATE TONIGHT AS RIDGE POKES IN. WESTERN MN WILL
BE MOST AT RISK FOR DROPPING BELOW FREEZING...AND FEW OF THE
TYPICAL FAVORED SPOTS MIGHT EVEN SEE SOME UPPER 20S...SUCH AS KMVE
TO KAQP AREA. WC MN INTO CENTRAL MN HAS A VERY RECENT HISTORY OF
TEMPS REACHING 32... EVEN FRIDAY MORNING. EXCEEDINGLY EXTENSIVE
COLLABORATION YIELDED DECISION TO HIT MENTION OF FROST IN
GRIDS/HWO/WX GRAPHIC BUT NO ADVISORY AT THIS TIME AS IMPACTS MAY
BE QUITE MINIMAL WITH SUCH RECENT COLD WX.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 421 AM CDT SAT MAY 11 2013

THE PERIOD BEGINS WITH HIGH PRESSURE OVERHEAD. SUNDAY SHOULD BE A
FINE DAY WITH LOW AFTERNOON HUMIDITY ALONG WITH LESS WIND FROM THE
NORTHWEST. THE HIGH WILL DRIFT EAST SUNDAY NIGHT WITH A FROSTY
MONDAY MORNING FOR PORTIONS OF EASTERN MN AND ALL OF WEST CENTRAL WI.
LOWS AT OR BELOW FREEZING ARE LIKELY IN THESE AREAS. THINGS WILL
BEGIN TO TURN AROUND ON MONDAY AS A WARM FRONT PUSHES EAST FROM
THE NORTHERN PLAINS. PLENTY OF SATURATION AND UPGLIDE SEEN IN THE
NAM/GFS 295/300K THETA SURFACES. HOWEVER... THE NAM FAILS TO
GENERATE MUCH IN THE WAY OF PRECIPITATION ALONG AND EAST OF I-94.
PREFERRED A SOLUTION CLOSER TO THE GFS/SREF WITH CHANCE POPS FOR
THE MORNING AND AFTERNOON HOURS. A POTENTIAL PROBLEM NOTED IN ALL
SOLUTIONS WAS THE HUGE INCREASE IN DEW POINTS FROM MONDAY INTO
TUESDAY WITH VALUES RISING FROM THE 30S TO THE 60S. WITH HIGH
PRESSURE BLOCKING GULF MOISTURE THIS SEEMS UNREASONABLE. IT IS
THOUGHT THAT THIS IS RELATED TO EVAPOTRANSPIRATION IN THE
MODELS... BUT WITH THE GROWING SEASON HARDLY STARTED... WE ARE
JUST NOT THERE YET. SO... MOS GUIDANCE AND CONSMOS WORKED AS A
STARTING POINT TO LOWER DEW POINTS DOWN FROM MONDAY THROUGH
WEDNESDAY.

IN THE WAKE OF THE WARM FRONT... TEMPERATURES WILL BE ON THE
INCREASE... WITH TUESDAY STILL LOOKING TO BE THE WARMEST DAY OF
THE NEXT SEVEN. PUSHED HIGHS UP A LITTLE ON TUESDAY WITH 90
DEGREES INDICATED FOR THE TWIN CITIES AND AREAS TO THE
SOUTHWEST. IN FACT... 90 TO 95 IS NOT OUT OF QUESTION BETWEEN THE
TWIN CITIES AND THE SOUTHWEST CORNER OF MN AS AN 850 MB THERMAL
RIDGE AROUND 22C PUSHES IN ON THE NAM/GFS AND EC. HIGHS TO OUR WEST
HAVE BEEN RUNNING 20 TO 25 DEGREES ABOVE THE 850 MB CONVERTED
TEMPERATURE WHICH WOULD PLACE US IN THE LOWER 90S. A FEW MORE DAYS
OF DRYING WILL HELP THE RUN UP AS WELL.

A WEAK COOL FRONT WILL MEANDER THROUGH TUESDAY NIGHT. ALTHOUGH WE
ARE CAPPED INITIALLY... ITS POSSIBLE SOME SHOWERS AND ISOLATED
THUNDERSTORMS MAY OCCUR LATER IN THE NIGHT AS THE MID LEVEL
THERMAL RIDGE MOVES EAST. HENCE...KEPT SMALL CHANCE POPS FOR THE
SE HALF OF THE CWA. LATER PERIODS ARE MORE TROUBLESOME AS SMALL
POPS POLLUTE THE FORECAST DURING EVERY PERIOD. HARD TO SEE WHERE
THEY ARE COMING FROM AS THE EC/GFS AND GEM ARE BASICALLY DRY UNTIL
FRIDAY. PROS AND CONS FROM OFFICES ON REMOVING THEM. THE CHANCES
ARE ACTUALLY BELOW CLIMATOLOGY. THE DECISION IN THE END WAS TO
STAY THE COURSE WITH THE CR EXTEND AS THE FLOW BECOME MORE ZONAL
FROM WEDNESDAY THROUGH FRIDAY ALONG WITH MINOR PERTURBATIONS.
HIGH TEMPERATURES WILL ALSO FALL BACK INTO THE 70S FOR THE LATTER
HALF OF THE WORK WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1250 PM CDT SAT MAY 11 2013

STRONG COLD ADVECTION WELL UNDER WAY AS AREA OF HIGH PRESSURE IS
SLIDING INTO THE DAKOTAS. DEEP MIXING HAS ALLOWED FOR STRONG NW
WINDS THIS AFTERNOON...AND EXPECT SPEEDS TO REMAIN AT THEIR
CURRENT LEVEL UNTIL BETWEEN 1Z AND 2Z. BY SUN MORNING...HIGH
PRESSURE WILL BE CENTERED OVER ERN SODAK. THIS WILL CUT BACK ON
GUSTS OVERNIGHT...BUT NAM SOUNDINGS EAST OF RWF AND AXN SHOWING
DEEP MIXING AND GUSTY NW WINDS RETURNING FOR SUNDAY...THOUGH AT
SPEEDS 10-15 KTS LOWER THAN TODAY. AS MIXING HAS INCREASED
TODAY...HAVE SEEN BKN DECK SCT OUT ACROSS MOST OF THE MPX MN AREA.
FOR WI TERMINALS...CORE OF COLD AIR ALOFT WILL BE DROPPING
OVERHEAD...WHICH WILL MAINTAIN BKN TO OVC SKIES THERE...WITH
WIDELY SCATTERED SHOWERS CONTINUING THROUGHOUT THE DAY OUT THERE
AS WELL. TONIGHT...SKIES CLEAR OUT AND WILL STAY THAT WAY WITH THE
EXCEPTION OF A RETURN OF CU LATE SUNDAY MORNING FOR EAU...WHERE
SLIGHTLY BETTER MOISTURE AND STEEPER LAPSE RATES WILL EXIST.

KMSP...SKIES STARTING TO SCT OUT AT TAF ISSUANCE TIME. BASED ON
NAM/RAP...EXPECT BANK OF BKN-OVC CIGS OVER NE MN/NRN WI TO DROP
THROUGH WI INTO THIS EVENING...SO STUCK WITH SCT CIG THE REST OF
THE DAY. ANY INSTABILITY SHOWERS WILL REMAIN SOUTH AND EAST OF THE
FIELD THE REST OF THE DAY AS WELL. WINDS DO CALM DOWN TONIGHT AND
BASED RETURN IN GUSTINESS SUNDAY ON MIXING FROM THE NAM BUFKIT
SOUNDING. NOT ANTICIPATING ANY CU TOMORROW AS BOUNDARY LAYER LOOKS
TOO DRY.

/OUTLOOK FOR KMSP/
MON...VFR. SLGT CHANCE SHRA. S-SW WINDS 10-15 KTS.
TUE...VFR. SW WINDS 10-15 KTS.
WED...VFR. WNW WINDS 10 KTS.

&&

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

$$

SHORT TERM...TDK
LONG TERM...RAH
AVIATION...MPG