Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 181105
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
605 AM CDT SAT OCT 18 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT SAT OCT 18 2014

QUIET SHORT TERM PERIOD AHEAD...WITH NO PRECIPITATION EXPECTED.
CURRENTLY...WIDESPREAD LOW LEVEL CLOUD COVER CAN BE SEEN FROM THE
GREAT LAKES THROUGH THE CENTRAL DAKOTAS DESPITE HIGH PRESSURE
BUILDING IN FROM CANADA.  CYCLONICALLY CURVED FLOW WILL REMAIN
OVERHEAD THROUGH THE MORNING HOURS...AND MODEL SOUNDINGS INDICATE
SIGNIFICANT DRYING TAKING PLACE IN THE MID AND UPPER LEVELS...BUT
PLENTY OF MOISTURE WILL REMAIN IN THE BOUNDARY LAYER AND IT WILL
TAKE UNTIL THE ANTI-CYCLONIC CIRCULATION COMBINED WITH WARMING
TEMPERATURES ARRIVE TO SCATTER OUT THE CLOUD DECK FROM MID DAY
THROUGH THE AFTERNOON.  THIS UPDATE INTRODUCED A SLIGHT DELAY IN
CLEARING SKIES FROM THE PREVIOUS FORECAST.  THE SURFACE TEMPS WILL
BATTLE THIS EXTENDED SKY COVER...SO SLIGHTLY LOWERED THE FORECAST
HIGHS FOR TODAY. WINDS WILL BE FROM THE NORTH INITIALLY...AROUND
5-10 KTS BUT THE ELONGATE CENTER OF THE SURFACE HIGH WILL WORK
ACROSS THE FA TODAY...SO EXPECT A FEW HOURS OF ESSENTIALLY CALM
WINDS /EARLY ACROSS THE WEST...LATER EAST/ BEFORE THEY TURN
SOUTHERLY ON THE BACK SIDE OF THE HIGH.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 329 AM CDT SAT OCT 18 2014

THE LONG TERM FORECAST WILL BE MILD AND DRY OVERALL...AS A LARGE
SCALE OMEGA BLOCK PATTERN PREVAILS FOR NEXT WEEK. THE ONLY
PRECIPITATION CHANCES WILL BOOKEND THE TIMEFRAME...WITH SUNDAY AND
THURSDAY APPEARING TO HAVE THE POTENTIAL TO PROVIDE A FEW SHOWERS
DURING THE TRANSITIONS INTO AND OUT OF THE BLOCKING PATTERN.

REGARDING SUNDAY PRECIPITATION CHANCES...MODELS HAVE CONTINUED TO
TREND TOWARD A DRIER SOLUTION FOR THE LOCAL AREA...WITH THE BETTER
MOISTURE/FORCING DISPLACED TO THE NORTH/EAST OF THE AREA. HAVE
RETAINED A SLIGHT CHANCE OF SHOWERS IN THE FAR NORTHEAST NEAR
LADYSMITH...BUT THE REMAINDER OF THE AREA SHOULD STAY DRY.

BY MONDAY...THE SURFACE LOW SHIFTS WELL EAST OF THE AREA...AND THE
MID LEVEL RIDGE WORKS INTO WESTERN MINNESOTA. HIGH TEMPERATURES
IN THE 55 TO 65 DEGREE RANGE WILL THEN BE COMMON THROUGH WEDNESDAY.

BY THURSDAY...A POTENT LITTLE SHORTWAVE PRESSES ACROSS THE ROCKIES
AND HIGH PLAINS...AND BRINGS AN END TO THE MID LEVEL RIDGING. THE 18.00Z
ECMWF WAS FASTER WITH THIS SCENARIO...AND BROUGHT SHOWERS INTO THE
AREA AS EARLY AS WEDNESDAY MORNING. MEANWHILE...THE 18.00Z GFS WAS
ABOUT 18 HOURS SLOWER WITH THE BAND OF RAIN. LEANED TOWARD THE
ECMWF ENSEMBLE AS THE PREFERRED SOLUTION....WHICH EXPANDS
PRECIPITATION EASTWARD ACROSS THE AREA ON WEDNESDAY AFTERNOON AND
NIGHT...AND LINGERS IT ON THURSDAY.

IN THE WAKE OF THIS SYSTEM...TEMPERATURES ARE UNAFFECTED...WITH
HIGHS IN THE 60S EXPECTED ON FRIDAY. THE CHANCE OF LOW
TEMPERATURES DIPPING BELOW FREEZING THROUGH THE EXTENDED FORECAST
PERIOD NEXT WEEK IS LOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 554 AM CDT SAT OCT 18 2014

THE FA WILL REMAIN SOCKED IN WITH MVFR CIGS THROUGH MUCH OF THE
MORNING ACROSS THE EAST...AND EVEN LONGER TO THE WEST. THE LATEST
NAM IS FAIRLY PESSIMISTIC IN TIMING THE SCATTERING OF THE CLOUD
DECK TODAY. I DO THINK IT MAY BE OVERDOING THE RH VALUES
INDICATED IN THE MODEL SOUNDINGS...BUT THE RAP HAD A GOOD HANDLE
ON THE CLOUD COVER FOR MUCH OF THE NIGHT SO LEANED THAT DIRECTION.
THIS RESULTED IN AN UPDATED FORECAST THAT EXTENDED THE MVFR CIGS
BY A FEW HOURS AT MOST SITES...BUT NOT AS LONG AS THE LATEST NAM
WOULD LIKE TO GO. SO THERE IS SOME DECENT UNCERTAINTY IN TIMING OF
THE CLOUD DECK SCATTERING. WESTERN MN REMAINS LOCKED IN WITH
THICKER CLOUD COVER SO IT WILL TAKE LONGER FOR IT TO SCATTER OUT.
NORTHERLY WINDS WILL BECOME LIGHT AND VARIABLE AS A SURFACE HIGH
PRESSURE AXIS WORKS ACROSS THE FA...THEN TURN SOUTHERLY LATER IN
THE PERIOD.

KMSP...CURRENT THINKING IS THAT THE CEILING WILL START BREAKING UP
AROUND NOON BUT CONFIDENCE IN THIS IS NOT HIGH. NAM SOUNDINGS
INDICATE THE POSSIBILITY OF THESE CEILINGS LASTING THROUGH MID
AFTERNOON.

/OUTLOOK FOR KMSP/
SUN...VFR. WINDS SW 10-15 KTS.
MON...VFR. WINDS NW 10 KTS.
TUE...VFR. WINDS SE 5-10 KTS.

&&

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

$$

SHORT TERM...SPD
LONG TERM...LS
AVIATION...SPD






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