Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 070508 AAB
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1208 AM CDT MON JUL 7 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 328 PM CDT SUN JUL 6 2014

COLD FRONT HAS BEEN MAKING STEADY PROGRESS TO THE EAST AT ABOUT 20
KTS ACROSS MN TODAY...AND AT 3PM WAS IN THE PROCESS OF WORKING
ACROSS THE TWIN CITIES. MORNING CLOUDS SLOWED DOWN THE WARMING IN
THE TWIN CITIES...BUT THERE IS STILL HOPE FOR OUR FIRST 90 DEGREE
TEMP THIS YEAR AS THERE WILL BE ABOUT A 2 HOUR WINDOW WHERE WE CAN
STILL WARM BEHIND THE FRONT BEFORE THE CAA KICKS IN. WE HAVE SEEN
PLACES LIKE REDWOOD FALLS...GLENCOE...AND NEW ULM HIT 90 IN THIS
ZONE AND IT WILL BE HITTING THE TWIN CITIES STILL DURING PEAK
HEATING BETWEEN 3 AND 5 PM...SO DON/T GIVE UP HOPE ON THAT FIRST
90 JUST YET!

AS FOR STORM POTENTIAL...ACTIVITY OVER WI HAS BEEN ELEVATED...WITH
THE ATMO STILL CAPPED WITH RESPECT TO SFC BASED CONVECTION PER THE
STABLE CU FIELD /AT 230 PM/ STILL IN PLACE OVER WHAT IS A VERY JUICY
WARM SECTOR...WHERE DEWPS HAVE BEEN COMMONLY RISEN UP INTO THE MID
70S. STILL LOTS OF DISAGREEMENT WITH WHETHER OR NOT THIS FRONT WILL
EVEN GENERATE CONVECTION...BUT GIVEN THE DEGREE OF INSTABILITY
PRESENT...ALONG WITH THE SHORTWAVE MOVING INTO WRN MN AS EVIDENCED
BY DRYING ON WATER VAPOR BACK ACROSS THE DAKOTAS...PREFER THE IDEA
THE HRRR AND MEMBER1 OF THE 15Z HOPWRF SHOW WITH A SCT LINE OF
STORMS DEVELOPING ALONG THE FRONT AROUND 20Z AND QUICKLY SPREADING
EAST. THIS WOULD PLACE THE THUNDER THREAT MAINLY ALONG AND EAST OF
AN ALBERT LEA TO RICE LAKE LINE. SFC WINDS HAVE VEERED CONSIDERABLY
DURING THE DAY...WHICH WILL RESULT IN A MINIMAL TORNADO THREAT...BUT
2K-4K J/KG OF MLCAPE...H7-H5 LAPSE RATES UP OVER 7 DEG C/KM...AND
EFFECTIVE SHEAR AROUND 40 KTS WILL BE MORE THAN ENOUGH TO SUPPORT A
WIND/HAIL THREAT...ESPECIALLY TOWARD THE IOWA BORDER WHERE
INSTABILITY AND LAPSE RATES ARE BETTER.

WILL SEE SKIES CLEAR OUT TONIGHT...BUT CONSISTENT NW WINDS WILL
BRING IN DEWPS IN THE LOWER/MID 60S...WHICH WILL LIMIT THE FOG
POTENTIAL. IN ADDITION...A VERY POTENT SHORTWAVE CURRENTLY OVER NRN
SASKATCHEWAN WILL DROP INTO NODAK TONIGHT...WITH ACTIVITY EXPECTED
TO DEVELOP OVER CENTRAL NODAK THIS EVENING. THIS WILL LIKELY SEND
SHOWERS/STORMS TOWARD CENTRAL MN LATE TONIGHT INTO MONDAY
MORNING...THOUGH MORE ROBUST STORM COVERAGE OVER THE MPX CWA IS NOT
EXPECTED UNTIL MONDAY AFTERNOON AS THAT STRONG SASKATCHEWAN WAVE
MOVES INTO WRN MN. FOR THIS WAVE...PREFERRED A GEM/ECMWF/GFS BLEND
FOR ITS TIMING. THE NAM IS ABOUT 6 HOURS FASTER WITH THE
WAVE...PLACING IT OVER ERN MN BY THE END OF THE SHORT TERM AS
OPPOSED TO WRN MN AS THE OTHER GUIDANCE SHOWS. DETERMINISTIC MODELS
SHOW FAIRLY WIDESPREAD CONVECTION DEVELOPING BASED ON THEIR QPF
FIELDS...BUT THE CAMS SHOW ACTIVITY BEING NOTICEABLY MORE SCATTERED
OVER MN MONDAY AFTERNOON. THIS IS LIKELY DUE TO THE FACT THAT THERE
REALLY IS NO STRONG SFC FEATURE TO FOCUS ACTIVITY DURING THE
AFTERNOON...SO THE CAMS ARE SIMPLY GENERATING CONVECTION WHERE THEY
CAN DEVELOP ENOUGH INSTABILITY.

THOUGH NW FLOW IS EXPECTED...1.5-2.5K J/KG OF MLCAPE COMBINED WITH
50-60 KTS OF BULK SHEAR WILL BE MORE THAN ENOUGH TO SUPPORT A SEVERE
THREAT. HODOGRAPHS FOR MONDAY ARE MOSTLY LONG STRAIGHT
LINES...INDICATING THE MAIN THREAT WOULD BE LARGE HAIL FROM
SPLITTING SUPERCELLS. IF ENOUGH STORMS CAN INITIATE...WE WOULD
LIKELY END UP WITH A COMPLEX OF STORMS OR TWO THAT WOULD HAVE A WIND
TREAT AS WELL. HIGHER LCLS /DUE TO THE DRIER BOUNDARY LAYER AIR
EXPECTED/ ALONG WITH THE SHEAR BEING MAINLY OF THE SPEED VARIETY
/WITH LITTLE DIRECTION CHANGE/ WILL GREATLY LIMIT ANY TORNADO
THREAT.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 328 PM CDT SUN JUL 6 2014

WHILE THE BEST STORM COVERAGE SHOULD GENERALLY BE BETWEEN 21-00Z
IN WESTERN MN...EASTERN MN WILL HAVE THE BEST SHOT AT THUNDER
BETWEEN 00-03Z...AND SHORTLY THEREAFTER IN WESTERN WI. THE MID-
LEVEL DRYING ARRIVES QUICKLY BETWEEN 03-06Z IN THE EASTERN
FORECAST AREA...SO THE PRECIP SHOULD GET QUICKLY SHUFFLED OFF TO
THE EAST LATE TOMORROW EVENING.

DRIER AND SLIGHTLY COOLER AIR ARRIVES BEHIND THE STORM SYSTEM ON
TUESDAY WITH SURFACE HIGH PRESSURE EXPANDING INTO THE PLAINS AND
UPPER LEVEL NORTHWEST FLOW. NORTHWEST WINDS WILL BE A LITTLE
BREEZY...OTHERWISE EXPECT MOSTLY SUNNY SKIES AND MILD TEMPERATURES
IN THE 70S TO NEAR 80 DEGREES. UPPER LEVEL RIDGING FLATTENS AS IT
SHIFTS INTO THE HIGH PLAINS ON WEDNESDAY...HOWEVER WITH RETURN
FLOW DEVELOPING IN WESTERN MN IN THE AFTERNOON HIGH TEMPERATURES
WILL IMPROVE A FEW DEGREES. THE EAST WILL REMAIN ON THE FRINGE OF
AN 850MN COLD POCKET CENTERED ROUGHLY OVER LAKE SUPERIOR. MID AND
HIGH CLOUDS BUILDING INTO THE AREA FROM THE WEST. MODEL
CONSISTENCY ISN`T AS GOOD LATER IN THE WEEK WITH WEST TO NORTHWEST
UPPER FLOW AND THE POSSIBILITY OF A FEW WEAK WAVES TO TRACK
THROUGH THE AREA. THE TIMING OF THESE WAVES REMAIN TOO DIFFICULT
TO PINPOINT WITH EACH MODEL SHOWING SLIGHTLY DIFFERENT
TIMING AND LATITUDINAL PLACEMENT - DID NOT REALLY ALTER THE POPS
MUCH WEDNESDAY NIGHT AND BEYOND. TEMPERATURES ARE EXPECTED TO
REMAIN WITHIN A FEW DEGREES OF CLIMATE NORMALS DURING THE PERIOD.
AFTER MONDAY...THE NEXT SUBSTANTIAL PROBABILITY FOR PRECIP ARRIVES
ON THURSDAY WHEN THE FLOW BECOMES A LITTLE MORE W-SW AND WARM
ADVECTION ARRIVES FROM THE DAKOTAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1155 PM CDT SUN JUL 6 2014

VFR CONDITIONS EXPECTED MOSTLY THROUGH THE PERIOD WITH BOUTS OF
DETERIORATING CONDITIONS POSSIBLE WITH SHOWER/THUNDERSTORM ACTIVITY
MONDAY AND MONDAY NIGHT. SKC IS FORECAST THROUGH MOST OF TONIGHT
WITH INCREASING CLOUDS LATE. A LEADING DISTURBANCE MAY BRING
SHOWERS INTO WESTERN MINNESOTA TOWARD DAWN...WITH ACTIVITY
BECOMING MORE WIDESPREAD AS THE AFTERNOON PROGRESSES. A LOT OF THE
HI RES MODELS KEEP THE TSRA SCATTERED WHICH MAKES IT DIFFICULT TO
FORECAST TIMING AT ANY GIVEN TAF LOCATION. WHILE IT IS LIKELY ALL
TAF SITES WILL EXPERIENCE THIS ACTIVITY AT SOME POINT MONDAY INTO
MONDAY EVENING...CONFIDENCE IS QUITE LOW ON MORE PRECISE DETAILS
AT THIS TIME.

KMSP...VFR CONDITIONS THROUGH THE PERIOD WITH THE POSSIBILITY OF
BRIEF INSTANCES OF IFR OR MVFR CONDITIONS IN SHRA/TSRA. KEPT MOST
OF THE PERIOD DRY UNTIL CONFIDENCE IN TIMING INCREASES.

/OUTLOOK FOR KMSP/
TUE...VFR. WIND NW 10 TO 20 KT.
WED...VFR. WIND NW 5 TO 15 KT.
THU...VFR. CHC TSRA OVERNIGHT. WIND S 10 TO 15 KT.

&&

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

$$

SHORT TERM...MPG
LONG TERM...CLF
AVIATION...BORGHOFF





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