Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 291805
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
105 PM CDT SAT AUG 29 2015

.UPDATE...
ISSUED AT 1123 AM CDT SAT AUG 29 2015

WE ARE GETTING A GREAT DEMONSTRATION IN HOW THE SUN IS LOSING ITS
POWER THIS MORNING AS STRATUS HAS BEEN MUCH MORE PERSISTENT THAN
ANYTHING BELIEVED IT WOULD BE. THE FACT THAT WE HAVE A SFC RIDGE
ASSOCIATED WITH THE STRATUS IS NOT HELPING EITHER AS IT HAS NOT
SUPPLIED US WITH ANY MECHANICAL MIXING. HOWEVER...SINCE ABOUT
1530 UTC...VIS SATELLITE TREND HAS SHOWN THE NW EDGE OF THE
STRATUS FINALLY STARTING TO ERODE. TWIN CITIES SHOULD CLEAR OUT BY
18Z...BUT THAT MAY NOT HAPPEN UNTIL 20/21Z DOWN TOWARD ALERT LEA.
AT 10AM...M0ST LOCATIONS UNDER THE STRATUS WERE STILL IN THE
50S...SO DID CUT BACK ON HIGHS UNDER THE STRATUS A FEW DEGREES.
OTHER THAN THAT...EVERYTHING ELSE IS ON TRACK!

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SAT AUG 29 2015

EXPECT A DRY FORECAST THROUGHOUT THE SHORT TERM WITH TEMPERATURES
CONTINUING TO INCREASE FROM THE PREVIOUS DAYS READINGS. AT FIRST
GLANCE THE AREA OF SHOWERS AND THUNDERSTORMS NORTH OF DULUTH HEADING
SOUTH COULD POSE A THREAT OF RAIN TO THE MN/WI COUNTIES ALONG AND
EAST OF I-35...BUT PARENT WAVE DRIVING THE STORMS WILL RACE TO THE
EAST...AND ALTHOUGH THE HIRES MODELS ARE STRUGGLING WITH THE CURRENT
PLACEMENT OF CONVECTION...THEY CONTINUE TO WEAKEN IT BETWEEN 09-
12Z...SO WILL HOLD TRUE TO THE DRY FORECAST.

THE MAIN CHALLENGE IN THIS TIME PERIOD WAS THE HANDLING OF
FOG/STRATUS THROUGH THE EARLY MORNING HOURS. LOW LEVEL MOISTURE WAS
INCHING UP FROM THE SOUTH...WITH SUB-1000FT CEILINGS. THE LAST
COUPLE RUNS OF THE HOPWRF CLOUD PROBABILITY SHOW THIS ENCROACHING
UPON EAU CLAIRE / TWIN CITIES THIS MORNING BEFORE DISSIPATING LATER
TODAY...SO TRIED TO REFLECT THAT IN THE CLOUD GRIDS.

LATER TODAY SOUTHWESTERLY FLOW AND WARM AIR ADVECTION WILL BRING
AFTERNOON HIGHS INTO THE LOW TO MID 80S ACROSS FAR WESTERN MN...WITH
UPPER 70S IN EASTERN MN AND WESTERN WI. AS WE FINISH OUT THE MONTH
OF AUGUST...SHORTER DAYS AND CLEAR CALM NIGHTS SHOULD FAVOR
RADIATIONAL FOG ACROSS THE REGION...SO REINTRODUCED PATCHY FOG FOR
LATE TONIGHT INTO SUNDAY MORNING.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT AUG 29 2015

UPPER LEVEL RIDGING WILL BE OVERHEAD AT THE START OF THE LONG
TERM WITH 24 DEG C AIR AT 850MB PUSHING INTO WEST CENTRAL AND
NORTHWEST MINNESOTA SUNDAY AFTERNOON. MID-DOWN FROM 900 MB YIELDS
HIGHS AROUND 90 FOR MADISON AND MORRIS AND THIS GOES ALONG WELL
WITH OBSERVED HIGHS IN THE WESTERN DAKOTAS FRIDAY AFTERNOON WITH
SIMILAR 850MB TEMPERATURES. THEREFORE...BLENDED IN THE MIX-DOWN
WITH RAW BLEND AND THE CURRENT FORECAST. THIS RAISED HIGHS SOME
FROM THE METROPOLITAN AREA ON NORTH THROUGH ST CLOUD AND MORA WITH
MIDDLE 80S FORECAST. THE COOLEST HIGHS ON SUNDAY STRETCH FROM
ALBERT LEA TO EAU CLAIRE WITH AROUND 80 TO THE LOWER 80S.

THE RIDGE WILL MOVE EAST OF US ON MONDAY WITH A WEAK COOL FRONT
MOVING ACROSS THE DAKOTAS. THIS BOUNDARY WILL MOVE INTO MINNESOTA
MONDAY NIGHT AND TUESDAY. THERE REMAINS A SMALL THREAT FOR SHOWERS
AND THUNDERSTORMS ALONG THE FRONT WITH THE BEST CHANCES OVER THE
NORTHEAST PORTION OF THE STATE AT THE NOSE OF THE LOW LEVEL
MOISTURE TRANSPORT. WE MAY STRUGGLE IN OUR FA TO SEE MUCH WITH A
RATHER PRONOUNCED WARM LAYER BETWEEN 800-700 MB.

MUCH OF THE REMAINDER OF THE WORKWEEK IS DRY ALONG WITH HIGHS IN
THE MIDDLE 80S. HOWEVER...THERE ARE SOME CAVEATS. THE BOUNDARY
ACROSS THE AREA ON TUESDAY WILL STALL AND BEGIN TO MOVE BACK NORTH
AS A WARM FRONT ON WEDNESDAY. WHILE THIS IS OCCURRING...A SHORT
WAVE WILL MOVE OUR WAY IN THE SOUTHWEST FLOW ALOFT...PASSING
ACROSS THE FA WEDNESDAY AFTERNOON AND NIGHT. THIS WILL OFFER
ANOTHER OPPORTUNITY FOR SOME SHOWERS AND THUNDERSTORMS ACROSS
EASTERN AREAS OF THE FA. ANOTHER CHANCE OF SHOWERS AND
THUNDERSTORMS IS INDICATED ON FRIDAY AS ANOTHER WEAK FRONT
APPROACHES FROM THE DAKOTAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 105 PM CDT SAT AUG 29 2015

COMBINATION OF THE EVER WEAKENING LATE AUGUST SUN AND A LACK OF
MECHANICAL MIXING WITH THE LIGHT WINDS HAS RESULTED IN THE STRATUS
BEING STUBBORN THIS MORNING. HOWEVER...IT IS NOW RAPIDLY MIXING
OUT AND IT WILL BE A THING OF THE PAST BY 19Z. NO WEATHER ISSUES
ARE THEN EXPECTED UNTIL TONIGHT...WHEN WE WILL LIKELY SEE A REPEAT
OF THE STRATUS EXPANSION. THU NIGHT THIS STRATUS AREA WAS IN
NORTH CENTRAL MN...LAST NIGHT IT MOVED TO OVER THE MPX AREA...AND
BASED ON SREF PROBS FOR CIGS UNDER 3K FT...THIS STRATUS AREA WILL
SETUP A BIT FARTHER SOUTHEAST TONIGHT. THIS WILL MEAN MORE OF THE
MPX TERMINALS WILL STAY OUT OF THE LOW CONDITIONS TONIGHT...WITH
MOST LIKELY LOCATIONS FOR STRATUS RETURNING BEING RNH/EAU. FOR
SUN MORNING...WE WILL HAVE A STRONGER PRESSURE GRADIENT AND
THEREFORE MORE SFC WINDS...SO ANY STRATUS WE DO SEE SUN MORNING
SHOULD MIX OUT QUICKER THAN IT DID TODAY.

KMSP...WE WILL QUICKLY GO VFR AND REMAIN AS SUCH THROUGH MUCH OF
TONIGHT. FULLY EXPECT ANOTHER ROUND OF STRATUS TO DEVELOP...BUT
LOOKS TO BE FARTHER SE THAN IT WAS THIS MORNING. AT THE
MOMENT...THINK MSP STAYS CLEAR OF THE STRATUS...ESPECIALLY
CONSIDERING WE WILL KEEP A LIGHT SOUTH WIND TONIGHT. STILL MAY BE
CLOSE SO ADDED A FEW003 TO THE CLOUD GROUP AT 11Z TO HINT AT THAT
POSSIBILITY AGAIN.

/OUTLOOK FOR KMSP/

MON-WED...VFR. WINDS S 5-15KT

&&

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

$$

UPDATE...MPG
SHORT TERM...JRB
LONG TERM...RAH
AVIATION...MPG



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