Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 090929
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
429 AM CDT WED APR 9 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT WED APR 9 2014

NOTE: THERE IS A FIRE WEATHER DISCUSSION BELOW AS WELL.

DECIDED TO INCREASE HIGH TEMPS TODAY BY 2-4 DEGREES BASED ON
00-06Z MODEL CONSENSUS...AND ADJUSTING FOR THE COOL BIAS OVER THE
PAST WEEK. THE COOL BIAS WITH FORECAST HIGHS WERE APPARENT IN BOTH
THE MPX FORECAST AND IN MOST OF THE AVAILABLE NUMERICAL GUIDANCE
ON SUNDAY AND MONDAY. OUR TEMPERATURE FORECAST TODAY IS ON THE
HIGH END OF THE MODEL SOLUTION ENVELOPE...WHICH IS A GOOD PLACE TO
BE ON DAYS LIKE TODAY. WE ALMOST NEVER GO WARM ENOUGH...AND MODEL
OUTPUT TENDS TO RUN AT LEAST A FEW DEGREES TOO COOL/MOIST WITH
TEMPS AND DEWPOINTS. WE USED A BLENDED MODEL FORECAST AND THEN
ADJUSTED UP 5 DEGREES BASED ON THE 925-850MB THERMAL PROFILE AND
STRONG MIXING POTENTIAL WITH THE SOUTHWEST FLOW. THERE IS A BATCH
OF 10KFT CLOUDS OUT THERE THIS MORNING...BUT WE THINK THIS WILL
CLEAR BY THE LATE MORNING AND LEAVE PLENTY OF TIME TO WARM DURING
THE AFTERNOON. THE THERMAL RIDGE DOESN`T ARRIVE IN FAR EASTERN MN
AND WEST CENTRAL WI UNTIL 18-00Z...SO BE PATIENT WITH THE WARMING
TODAY IN THESE AREAS. WE MIGHT END UP WITH HIGHS CLOSER TO
4-4:30PM...RATHER THAN 2-3PM. BEHIND THE WARM AND BREEZY
CONDITIONS TODAY WILL COME A COLD FRONT LATE THIS EVENING/TONIGHT.
MOISTURE IS LIMITED...SO WE COULDN`T REALLY JUSTIFY RAISING POPS
TOO MUCH FROM WHAT THE PREVIOUS FORECAST HAD FOR TONIGHT. WE DID
INCLUDE LIKELY LIGHT RAIN SHOWERS IN THE FORECAST BASICALLY ALONG
AND NORTH OF I-94 WHERE POST-FRONTAL SATURATION LOOKS MORE LIKELY.
SOUTH OF HERE WE HAVE SLIGHT-CHANCE POPS AND A LOT OF THE GUIDANCE
SHOWS LIGHT QPF...BUT PRECIP WILL STRUGGLE TO REACH THE GROUND AND
THERE MIGHT BE A LOT OF VIRGA. MOST AREAS THAT SEE RAIN TONIGHT
WILL BE IN THE TRACE-0.04" RANGE.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CDT WED APR 9 2014

FIRST OFF...IT`S NICE TO SEE THE 09.00Z ECMWF MOSTLY REMOVED THE
TWO SNOW EVENTS IT HAD LOCALLY OVER THE NEXT 7-10 DAYS. RUN-TO-RUN
CONSISTENCY IN ACCUMULATING SNOW WAS STARTING TO GARNER SOME
ATTENTION. OVERALL...THE EXTENDED MODEL OUTPUT IS STILL NOT
OPTIMISTIC IN MAINTAINING ANY SORT OF WARMTH AS WE TRANSITION FROM
SPLIT FLOW THROUGH THE WEEKEND TO A PRONOUNCED CENTRAL/EASTERN
CONUS TROUGH. THIS WOULD LEAD TO SIGNIFICANT COLD DEPARTURES FROM
NORMAL /POTENTIALLY AS COLD AS 20-25 BELOW NORMAL/ FOR A COUPLE
DAYS. THIS IS ESPECIALLY TRUE IF YOU BY THE SLOWER...DEEPER ECMWF.
THOSE 850 MB TEMPS EARLY TO MID WEEK ARE MORE REPRESENTATIVE OF
FEBRUARY. THE GFS ISN`T QUITE IS BAD MON-WED...BUT THERE ARE SOME
GLARING SOLUTION DIFFERENCES.

THERE ARE A COUPLE DECENT CHANCES FOR RAIN IN THE EXTENDED. THERE
IS A WEAK TROUGH PASSING THROUGH ON FRIDAY...BUT THE FORCING ISN`T
OVERLY STRONG. WE COULD STILL SHAKE OUT A FEW LIGHT SHOWERS. THE
BETTER CHANCE OF SHOWERS AND STORMS COMES ON SATURDAY WITH A
DEVELOPING SURFACE LOW IN THE PLAINS AND RESPECTABLE 925-850MB
MOISTURE TRANSPORT NOSING UP INTO THE FORECAST AREA. WE SHOULD
ALSO STEEPEN MID LEVEL LAPSE RATES WITH 20-40DM HEIGHT FALLS
DURING THE DAY. SO...THERE SHOULD AT LEAST BE A FEW HUNDRED JOULES
OF ELEVATED CAPE. THERE FORCING WILL ALSO BE OVER A LARGE
AREA...SO IF THE SIGNAL CONTINUES TOMORROW WE WILL PROBABLY NEED
TO MOVE TOWARD LIKELY POPS ON SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1101 PM CDT TUE APR 8 2014

VFR XPCTD THRU THIS TAF PERIOD FOR ALL BUT KAXN DUE TO EARLY
EVENING INCOMING CONVECTION. AHEAD OF THAT FOR THE REST OF THE
OVERNIGHT THRU MUCH OF THE DAY WEDNESDAY...SKIES MOSTLY CLEAR THRU
DAYBREAK TMRW...THEN HIGH CLOUDS STREAM IN FROM THE W AHEAD OF A
CDFNT. MID-TO-UPR LVL CIGS DEVELOP LATE OVER WRN MN...BUT SCT
CLOUDS LOOK TO PREVAIL FOR CENTRAL-ERN MN INTO WRN WI TMRW. IN WRN
MN...SCTD SHWRS/ISOLD TSTMS INFILTRATE THE AREA AFTER 00Z AND THIS
WILL IMPACT MAINLY KAXN. CONFIDENCE TOO LOW TO GO WITH VSBY LOWER
THAN VFR BUT DID INDICATE MVFR CEILING. WINDS WILL BE ANOTHER CONCERN
AS THEY START OUT BACKING TO S WITH SPEEDS DROPPING TO ARND 5 KT
OVERNIGHT. WINDS REMAIN SLY THRU DAYBREAK AND INCRS TO ARND 10
KT. AFTER DAYBREAK...STRONG SW WINDS DEVELOP WITH SPEEDS APCHG
20G30KT...AND SUCH SPEEDS REMAIN FAIRLY CONSISTENT TMRW AFTN AND
EVE AS WINDS VEER SLIGHTLY TO W LATE.

KMSP...VFR THROUGHOUT...ALTHOUGH MIDLVL CEILINGS DEVELOP LATE WED
EVE INTO THU MRNG AHEAD OF AN APCHG CDFNT AND SOME SCTD -SHRA ARE
POSSIBLE. WINDS BACK TO S ARND MIDNIGHT WHILE SPEEDS DROP TO NEAR
5 KT. STRONGER SPEEDS XPCTD ARND SUNRISE TMRW...AND SPEEDS
CONTINUE TO INCRS WHILE VEERING TO 210-230 TMRW AFTN. PREVAILING
WLY XPCTD BY TMRW EVE WITH SLIGHTLY DIMINISHED SPEEDS. AS FOR
CLOUDS...SKIES CLEAR OUT OVERNIGHT THEN HIGH CLOUDS DEVELOP DURG
THE DAY TMRW WITH UPR- LVL CIGS LIKELY BY TMRW EVE THEN CIGS DROP
GOING INTO TMRW NGT.

/OUTLOOK FOR KMSP/
THU...VFR. CHC MVFR CIGS/SHRA EARLY. WINDS NW 10-20 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
SAT...MAINLY VFR. CHC MVFR CIGS/SHRA. WINDS S 10-15 KTS.

&&

.FIRE WEATHER...
ISSUED AT 340 AM CDT WED APR 9 2014

AFTER COLLABORATION WITH NEIGHBORS...DECIDED TO EXPAND THE RED FLAG
WARNING ACROSS MOST OF THE WIND FAVORED AREAS. THE WEATHER ELEMENT
WITH THE LARGEST AMOUNT OF UNCERTAINTY IS STILL THE HUMIDITY. TOOK A
FAIR AMOUNT OF WORK IN THE GRIDS TO GET HUMIDITIES DOWN INTO THE
20-25 PERCENT RANGE THIS AFTERNOON. IN THESE TYPES OF WEATHER
PATTERNS...FORECAST MODELS RUN A COOL/MOIST BIAS...THE BIG QUESTION
FOR TODAY IS WHETHER OR NOT WE OVER CORRECTED FOR SAID COOL/MOIST
BIAS. FOR THE CURRENT HUMIDITY FORECAST TO WORK OUT...WE WILL NEED
TO SEE MIXING HEIGHTS BUILD TO ABOVE 800 MB AS THE RAP AND NAM
INDICATE AND ALSO HOPE WE DO NOT SEE TOO MUCH POOLING OF MOISTURE
AHEAD OF THE COLD FRONT THAT WILL BE DROPPING SOUTHEAST ACROSS
NODAK/NW MN BY THE AFTERNOON. GIVEN WINDS GUSTING TO BETWEEN 30-35
MPH WITH AFTERNOON HUMIDITIES FALLING TO AROUND 25 PERCENT...IT WAS
DECIDED BY ALL OFFICES TO ERR ON THE SIDE OF CAUTION AND GO WITH THE
EXPANDED RED FLAG WARNING. CONFIDENCE IS HIGHEST IN RED FLAG
CRITERIA BEING MET IN SW MN /WHERE INITIAL WARNING WAS ISSUED/ AND
DOES GRADUALLY DECREASE SOME AS YOU HEAD EAST.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...RED FLAG WARNING FROM NOON TODAY TO 6 PM CDT THIS EVENING FOR
     MNZ047-048-054>058-064>067-073>078-082>085-091>093.

WI...NONE.
&&

$$

SHORT TERM...CLF
LONG TERM...CLF
AVIATION...JPC
FIRE WEATHER...MPG







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