Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 242004
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
304 PM CDT MON AUG 24 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 304 PM CDT MON AUG 24 2015

QUASI-STATIONARY LOW PRESSURE SYSTEM POSITIONED JUST NORTH OF LAKE
SUPERIOR CONTINUES TO CYCLE THE CLOUD COVER SOUTHWARD THROUGH
EASTERN MINNESOTA AND ALL OF WISCONSIN...WITH THE BACK EDGE OF THE
CLOUD LINE DRAPED FROM LONG PRAIRIE...THROUGH ST CLOUD...THE WEST
SIDE OF THE TWIN CITIES...TOWARD ROCHESTER.  THE SURFACE LOW WILL
VERY SLOWLY DRIFT EAST THROUGH TOMORROW.  THE CLOUD DECK WILL LIKELY
REMAIN IN PLACE THROUGH THE REST OF THE AFTERNOON...AND BEGIN
PUSHING EAST THIS EVENING.  THE BLUSTERY WINDS WE ARE EXPERIENCING
THIS AFTERNOON WILL NOTICEABLY WEAKEN AT ABOUT THE SAME TIME THEY
DID LAST EVENING...AROUND 7-8PM.  OVERNIGHT...TEMPERATURES FALLING
INTO THE 40S ACROSS WESTERN MN ARE ONCE AGAIN LIKELY WITH DEW POINTS
ALREADY STEADY IN THE MID 40S...AND THE SURFACE HIGH BEGINNING TO
PUSH IN. FURTHER EAST...MORE CLOUD COVER AND SLIGHTLY MORE WIND WILL
KEEP TEMPERATURES JUST A COUPLE DEGREES WARMER...BUT STILL A COOL
MORNING EXPECTED AGAIN TOMORROW NONETHELESS. THERE WILL STILL BE
ENOUGH OF A PRESSURE GRADIENT TO KEEP WIND SPEEDS AROUND 5 TO 10
MPH.  WITH THE HIGH PUSHING INTO WESTERN MN TOMORROW...THE GRADIENT
WILL SLACKEN FURTHER ACROSS WESTERN MN...SO MOST OF THE AREA CAN
EXPECT WIND SPEEDS OF 10-15 MPH WITH MUCH WEAKER GUSTS THAN TODAY.
TEMPERATURES WILL REMAIN BELOW AVERAGE UNDER THE NORTHWEST FLOW
REGIME...BUT MORE ABUNDANT SUNSHINE WILL ALLOW DAYTIME HIGHS TO
ECLIPSE 70 DEGREES ACROSS SOUTHERN MN...BUT COOLER IN WESTERN WI
WHERE THE CLOUD COVER MAY REMAIN THROUGH MUCH OF THE DAY.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 304 PM CDT MON AUG 24 2015

THE MAIN CONCERN IN THE LONG TERM IS A COMPACT UPPER LOW PASSING
ACROSS THE REGION IN THE THURSDAY THROUGH SATURDAY PERIOD. THE GFS
REMAINS THE NORTHERN MOST SOLUTION WITH THIS FEATURE...PASSING IT
ACROSS SD AND FAR SOUTHERN MN/IA. THE CANADIAN AND ECMWF REMAIN ON
A TRACK ACROSS NE AND IA. THE FIM MODEL SPLITS THE DIFFERENCE
BETWEEN THE FOREIGN AND DOMESTIC SOLUTIONS. ALL OF THE SOLUTIONS
WOULD HAVE SHRA/TSRA FOR US...WITH HIGH CHANCE TO LIKELY POPS
FROM LATE THURSDAY NIGHT AND FRIDAY. THE PROBLEM IS THE FACT THAT
PW VALUES ONCE AGAIN ARE PROGGED TO RISE TO THE MAX MOVING AVERAGE
FOR KMPX AT AROUND 1.8 INCHES. THIS COMPACT UPPER FEATURE HAS A
POTENT RIGHT ENTRANCE REGION WITH THE JET ALONG WITH STRONG
DIFFERENTIAL DIVERGENCE. HENCE...PRECIPITATION RUN TOTALS ARE
QUITE HEAVY WITH 3 TO 5 INCHES ACROSS PORTIONS OF EASTERN NE AND
WESTERN IA ON THE CANADIAN AND ECMWF WITH 2 TO 3 INCHES ACROSS
NORTHERN IA AND SOUTHERN MN ON THE GFS. THEREFORE...THE TRACK IS
CRITICAL. DP/DT OVER THE PAST TWO DAYS SHOWS THE ECMWF AND
CANADIAN HAVE HELD THEIR GROUND WITH THE GFS DRIFTING SOUTHWARD
WITH EACH RUN. THE CIPS ANALOGS USING THE GFS AT 84 HOURS SHOWS
THE PERCENTAGE OF THE TOP 15 ANALOGS EXCEEDING THE 48 HOUR UNIFIED
PRECIPITATION DATA SET OF GREATER THAN 1 INCH HIGHEST FROM KOMA
THROUGH KDMX. PERHAPS THE SOUTHERN SOLUTIONS WILL BE MORE CORRECT.

PRECEDING THIS PRECIPITATION EVENT WILL BE A CONTINUATION OF THE
COOL WEATHER PATTERN FOR TUESDAY NIGHT AND WEDNESDAY. A SURFACE
RIDGE AXIS WILL BE OVER US WEDNESDAY MORNING...SO LOWS IN THE 45
TO 50 DEGREE RANGE WILL BE COMMON ALONG WITH MUCH LESS WIND
DURING THE DAY.

IN THE WAKE OF THE LATE WEEK PRECIPITATION EVENT...SOUTHERLY
SURFACE WINDS COMBINED WITH INCREASING HEIGHTS ALOFT WILL BECOME
ENTRENCHED ACROSS THE REGION FOR THE WEEKEND AND NEXT MONDAY. THIS
WILL BRING A RETURN OF HIGH TEMPERATURES CLOSER TO OR EVEN ABOVE
SEASONAL LEVELS. DRY WEATHER IS FORECAST FOR THE WEEKEND AND
MONDAY AS WELL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM CDT MON AUG 24 2015

THE LOW PRESSURE CENTER CONTINUES TO SIT JUST NORTH OF LAKE
SUPERIOR...ROTATING THE CLOUDS IN FROM THE NORTH. THE BACK EDGE OF
THE CLOUD DECK LITERALLY INTERSECTS THE HEART OF THE TWIN
CITIES...WITH MSP GENERALLY SEEING BROKEN CEILINGS...BUT
OCCASIONALLY SCATTERED. THIS TREND WILL CONTINUE THROUGH THE
AFTERNOON...BUT THE CLOUD BASE WILL BE VFR...AROUND 5-6 KFT
SIMILARLY TO YESTERDAY. THE SAME CAN BE SAID FOR THE ST. CLOUD
AREA...RIGHT ON THE EDGE OF THE CLOUD DECK THROUGH THE AFTERNOON.
FOR AREAS EAST...THE CLOUDS WILL BE SLOW TO DEPART THROUGH
TOMORROW...ESPECIALLY IN EAU CLAIRE. WESTERN MN LOCATIONS WILL
CONTINUE TO SEE MOSTLY CLEAR SKIES. THE WIND ACROSS THE REGION
WILL CONTINUE TO BE BLUSTERY FROM THE NORTHWEST...AND WILL
DIMINISH SIGNIFICANTLY THIS EVENING AS THE SUN ANGLE DECREASES.
THE HIGH PRESSURE TO OUR WEST WILL FINALLY START TO PUSH IN
TOMORROW...MEANING THOSE CLOUDS WILL DRIFT OFF TO OUR EAST...AND
WE WILL HAVE NORTHWEST WINDS...BUT A BIT WEAKER THAN TODAY.

KMSP...STRADDLING THE EDGE OF THE CLOUD DECK WILL CONTINUE INTO
THE EVENING...BUT OVERNIGHT WE EXPECT THE CLOUDS TO START MOVING
TO THE EAST. WINDS WILL FOLLOW THE SAME TREND AS YESTERDAY
EVENING...DIMINISHING QUICKLY IN THE EVENING.

/OUTLOOK FOR KMSP/
WED...VFR. WIND W/SW 5-10KT.
THU...VFR. WIND S AT 10-15KT.
FRI...MVFR PSBL. CHC SHRA. WINDS SE 5-10KTS.

&&

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

$$

SHORT TERM...SPD
LONG TERM...RAH
AVIATION...SPD


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