Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 261117
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
517 AM CST THU FEB 26 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM CST THU FEB 26 2015

QUIET WEATHER EXPECTED DURING THE SHORT TERM AS A 1045 MB HIGH
CURRENTLY OVER WESTERN SASKATCHEWAN WILL DRIFT SE TO CENTRAL IOWA BY
12Z FRIDAY. NOT EXPECTING ANY CLOUD COVER DURING THE PERIOD
EITHER...AS HI-RES MODELS AND THE NAM ARE OVERDOING EXTENT OF LOW
LEVEL MOISTURE. WITH CONTINUED DRY ADVECTION AND SUBSIDENCE ON NW
WINDS...ALONG WITH SNOW COVER...DO NOT SEE US DEVELOPING A STATOCU
FIELD TODAY. FOR TEMPERATURES...NAM SHOWS US MIXING UP TO ABOUT 900
MB. MIXING DOWN FROM THAT LEVEL FOR HIGHS TODAY YOU GET WHAT WAS
ALREADY IN THE FORECAST...HIGHS BETWEEN 25 AND 30 DEGREES BELOW
NORMAL. TONIGHT...THE PRESSURE GRADIENT WILL RELAX...ALLOWING FOR
THE POTENTIAL TO DECOUPLE. DID NOT CHANGE THE EXISTING FORECAST
MUCH...WHICH WAS ALREADY ON THE COLD SIDE OF GUIDANCE.
DETERMINISTIC MODELS SHOW MOST AREAS MAINTAINING A 5 KT WIND
OVERNIGHT AND IF THAT HAPPENS...THEN WE MAY BE SEVERAL DEGREES TOO
COLD WITH LOWS FOR TONIGHT. THE LAST TIME WE HAD A SIMILAR
RADIATIONAL COOLING NIGHT ON SUNDAY NIGHT...THE BEST VERIFYING
MODELS WERE A BLEND OF THE BIAS CORRECTED MAV/MET FORECASTS...WHICH
IS SEVERAL DEGREES WARMER THAN WHAT WE CURRENTLY HAVE. IT SHOULD BE
NOTED THOUGH THAT THOSE BIAS CORRECTED GRIDS HAVE BEEN TRAINED ON A
LANDSCAPE THAT LACKED MUCH IN THE WAY OF SNOW COVER SW OF I-94...SO
THAT BLEND MAY NOT WORK OUT AS WELL THIS TIME.

AS FOR THE WIND CHILL ISSUES. CURRENT WIND CHILL ADVY FOR THIS
MORNING IS STILL MORE THAN SUPPORTED IN THE FORECAST. WE SHOULD SEE
THE COLDEST WIND CHILLS JUST AFTER SUNRISE AS WINDS PICK UP
SOME...WITH VALUES DIPPING TO BETWEEN 25 AND 35 BELOW IN THE ADVY.
OUTSIDE OF THE ADVY...WE WILL LIKELY SEE SPOTTY LOCATIONS HIT -25
FOR A WIND CHILL...BUT WITH THAT NOT EXPECTING TO BE VERY
WIDESPREAD...STILL FELT COMFORTABLE WITH KEEPING THE AREAS CURRENTLY
OUT OF THE ADVY HEADLINE FREE.

AS FOR TONIGHT...THE WINDS WILL BE LIGHTER...BUT CURRENT FORECAST
LOWS ARE SEVERAL DEGREES COLDER THAN TONIGHT...SO WE WILL BE RIGHT
BACK IN THE SAME BOAT WITH APPARENT TEMPS DOWN IN THAT -25 TO -30
RANGE. CURRENT GRIDS WOULD SUGGEST A WIND CHILL ADVY WOULD BE NEEDED
FOR TONIGHT IN OUR TYPICAL WINDY AREAS FROM WEST CENTRAL INTO SOUTH
CENTRAL MINNESOTA. HOWEVER...WITH UNCERTAINTIES WITH JUST HOW COLD
WE WILL GET ALONG WITH HOW MUCH WIND WE WILL ABLE TO KEEP...WILL
HOLD OFF ON ANY DECISIONS ON A WIND CHILL ADVY FOR TONIGHT UNTIL THE
CURRENT ONE PLAYS ITSELF OUT THIS MORNING.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CST THU FEB 26 2015

HIGH PRESSURE WILL BE SLIDING SOUTHEAST OVER THE OHIO VALLEY FRIDAY
WHICH WILL MARK THE BEGINNING OF A MILDER PERIOD NEXT WEEK. THE
STUBBORN CENTRAL AND EASTERN CONUS TROUGH WILL GRADUALLY BECOME A
PRETTY DECENT RIDGE OVER THE GOM AND THE CARIBBEAN EARLY NEXT
WEEK. THIS WILL BRING A MARKED NORTHWARD SHIFT IN THE STORM TRACK.
THUS...THE TRANQUIL CONDITIONS THIS MONTH WILL BECOME A BIT MORE
ACTIVE AS THE CALENDAR SHIFTS TO MARCH.

DESPITE A RETURN FLOW BECOMING ESTABLISHED...FRIDAY WILL STILL BE
A GOOD 15-20 DEGREES BELOW AVERAGE WITH HIGHS ONLY IN THE LOW TO
MID TEENS. IT ISN/T REALLY UNTIL SUNDAY WHEN TEMPS RETURN TO A
RESPECTABLE DEPARTURE FROM AVERAGE...ALBEIT STILL 5-10 DEGREES ON
THE NEGATIVE SIDE.

A POSITIVELY TILTED TROUGH DEVELOPING IN THE SOUTHWEST WILL HOUSE
A LOT OF ENERGY DURING THE LONG TERM. PIECES OF THIS ENERGY WILL
BREAK LOOSE AND DEVELOP INTO CYCLONES FURTHER EAST ACROSS THE
CENTRAL PLAINS. THE FIRST SYSTEM IS STILL LARGELY EXPECTED TO MISS
THE LOCAL AREA TO THE SOUTH SATURDAY NIGHT AS A TROUGH SHIFTING
EAST ALONG THE NORTHERN CONUS WILL SUPPRESS THE THE BEST FORCING
AND MOISTURE SOUTH. NONETHELESS...MAINTAINED POPS ACROSS SRN MN
INTO WRN WI WHERE THE BEST POTENTIAL WILL BE FOR A PERIOD LIGHT
SNOW. UP TO AN INCH WILL BE POSSIBLE...BUT MOST OF THE MODELS ARE
ONLY SHOWING TRACE TO HALF INCH AMOUNTS.

THE BETTER SYSTEM TO WATCH WILL BE MONDAY NIGHT INTO TUESDAY.
DETERMINISTIC GLOBAL MODELS HAVE COME INTO SLIGHTLY BETTER
AGREEMENT OVERNIGHT ALTHOUGH SPREAD DOES REMAIN WITHIN THEIR
ENSEMBLE SOLUTIONS. WHILE THE RIDGE CONTINUES TO BUILD OVER THE
GOM...A REINFORCING TROUGH DIVING DOWN THE WEST COAST WILL EJECT
MORE ENERGY NORTHEAST INTO THE PLAINS LATE MONDAY. WHAT MODELS
HAVE BEEN SHOWING PERHAPS MOST CONSISTENTLY RECENTLY IS A
CONTINUED POSITIVELY TILTED TROUGH THROUGHOUT ITS EVOLUTION...
RESULTING IN A LESS-DEVELOPED SURFACE SYSTEM TUESDAY AS IT HEADS
NORTHEAST FROM KANSAS INTO THE LOWER GREAT LAKES. ONLY TIME WILL
TELL IF THIS WILL HOLD...BUT A SECONDARY INTERACTION WITH THE
APPROACHING NORTHWEST TROUGH COULD BRING A MORE ROBUST SYSTEM THAN
MODELS ARE CURRENTLY PROJECTING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM CST THU FEB 26 2015

HIGH CONFIDENCE IN TAFS AS SUBSIDENCE AND DRY AIR FROM INCOMING
HIGH PRESSURE WILL KEEP SKIES. HIGH RES MODELS SUCH AS THE HRRR
ARE WAY TO OVERDONE WITH STRATOCU DEVELOPMENT THIS AFTERNOON...SO
STUCK WITH WITH LAMP IDEA OF SKC CONDITIONS.

KMSP...CONFIDENCE HIGH IN TAFS WITH NO SIGNIFICANT DEVIATIONS FROM
FORECAST EXPECTED.

/OUTLOOK FOR KMSP/
FRI...VFR. WINDS WSW AT 5-10 KTS.
SAT...VFR. WINDS S AT 15 KTS.
SUN...VFR. WINDS W AT 10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ041-042-047>049-
     054>057-064-065-073.

     WIND CHILL ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ043>045-
     050-052-053-058-074-082-091.

WI...WIND CHILL ADVISORY UNTIL 10 AM CST THIS MORNING FOR WIZ014>016.

&&

$$

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


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