Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 172052
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
252 PM CST WED DEC 17 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 245 PM CST WED DEC 17 2014

A LONG WAVE SHEAR AXIS THAT HAD AN ASSOCIATED AREA OF
CLDS/FLURRIES WAS ACROSS PORTIONS OF EC/CENTRAL MN AND INTO WC WI.
BASICALLY ALONG AND NORTH OF I-94. THERE HAS BEEN A SLOW DECREASE
IN THE CLOUD COVER THIS AFTN...BUT NOT ENOUGH TO WARRANT
CLR/CLEARING SKIES TONIGHT. WHERE THE SKIES HAVE REMAINED CLEAR
TODAY AND WINDS REMAIN LIGHT AND VARIABLE TONIGHT...SFC TEMPS WILL
LIKELY FALL QUICKLY. DEBATED ON SOME OF THE LOCAL MODELS /MPXWRF
AND HOPWRF/ FOR SFC LOWS TONIGHT /-2F TO -8F/...BUT THESE SEEM TO
LOW...ESPECIALLY CONSIDERING DEW PTS ARND 10 DEGREES. HAVE OPTED
TO LOWER TEMPS SLIGHTLY FROM THE PREVIOUS FORECAST...WITH NEAR
ZERO IN WC/SW MN WHERE CLR SKIES/LIGHT WINDS AND HIGHER SNOW PACK
WILL LEAD TO LOWER TEMPS. ELSEWHERE...TEMPS WILL BE A FEW DEGREES
COOLER THAN PREVIOUSLY FORECAST.

A STORM SYSTEM MOVING ACROSS THE CENTRAL/SOUTHERN PLAINS WILL
PROVIDE MORE CLOUD COVER ON THURSDAY AS WINDS SHIFT TO THE SE AS
THE SFC HIGH MOVES OFF TO THE EAST.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 245 PM CST WED DEC 17 2014

FAIRLY QUIET WEATHER WITH A GRADUAL WARMUP IS EXPECTED THROUGH THE
WEEKEND...WITH MORE ACTIVE AND COOLER WEATHER EXPECTED FOR THE DAYS
HEADING INTO CHRISTMAS.

FOR THE GENERAL PATTERN EVOLUTION...THE BIG HIGHLIGHT FROM BOTH THE
GFS AND ECMWF IS THE DEVELOPMENT OF A MORE AMPLIFIED PATTERN NEXT
WEEK...WITH ERN PAC RIDGING AND NOAM TROUGHING MAKING A RETURN. YOUR
TYPICAL TIMING/STRENGTH DETAILS STILL EXIST...BUT IN
GENERAL...MEDIUM RANGE MODELS SHOW A RATHER BAGGY AND DISORGANIZED
SERIES OF SHORTWAVES WORKING ACROSS THE AREA FRIDAY THROUGH SUNDAY.
ON SUNDAY...THE RIDGE/TROUGH PATTERN WILL START TAKING SHAPE...WITH
A STRONGER WAVE BEGINNING TO IMPACT THE AREA SUNDAY NIGHT. THIS
TROUGH SUNDAY NIGHT LOOKS TO GO THROUGH A PERIOD OF INTENSIFICATION
MON/TUE AS IT MERGES WITH AN UPPER WAVE COMING OUT OF THE SRN
PLAINS...WITH THIS WAVE DEVELOPING INTO A RATHER DEEP CLOSED H5 LOW
OVER THE GREAT LAKES ON WEDNESDAY. THE MAIN DIFFERENCE BETWEEN THE
GFS/ECMWF IS ONE OF TIMING...WITH THE ECMWF BEING SLOWER AND FARTHER
WEST/SOUTH WITH WHERE THIS DEEPENING OCCURS.

MAIN THING EXPECTED TO CHANGE WITH THE WEATHER FRIDAY AND SATURDAY
IS THAT THE BANK OF STRATUS CURRENTLY SPLAYED OUT ACROSS BOTH THE
CANADIAN AND U.S. HIGH PLAINS WILL BE WORKING ACROSS THE UPPER MIS
VALLEY AS THE SFC RIDGE CURRENTLY NUDGING INTO WRN MN MOVES INTO THE
GREAT LAKES. THIS WILL AGAIN LIMIT THE DIURNAL RANGE IN
TEMPERATURES. HAVE ALSO KEPT BOTH DAYS DRY. FRIDAY..THE PRIMARY
UPPER WAVE AND SUPPORT FOR LIFT WILL BE GOING ALONG THE
INTERNATIONAL BORDER. IN ADDITION...WHAT LITTLE LIFT/MOISTURE THERE
IS AROUND THE 290K SFC IS CENTERED IN NE MN...WHERE THE 17.15 SREF
DOES SHOW SOME LOW PROBABILITIES FOR MEASURABLE PRECIP. KEPT
SATURDAY DRY AS WELL...THOUGH CONTINUED SOUTHERLY WINDS AND WAA
COULD LEAD TO THE GENERATION OF LIGHT PRECIP...THOUGH WITH NO DEEP
MOISTURE IT WOULD BE DRIZZLE.

HAVE PRECIP CHANCES RETURNING SUNDAY FOR THE ERN HALF OF THE AREA AS
THIS IS WHEN WE START SEEING DEEPER MOISTURE FROM THE GULF STARTING
TO WORK UP INTO THE AREA...THOUGH UPPER FORCING STILL LOOKS TO BE
LACKING...SO THIS WOULD BE LIGHT AT BEST.

PRECIP CHANCES ARE STARTING TO LOOK BETTER STARTING SUNDAY
NIGHT...LASTING ALL THE WAY OUT INTO WEDNESDAY. COMPARED TO 24 HOURS
AGO...THERE HAS BEEN A SOUTHWARD SHIFT IN THE MODELS...BUT IN THE
LAST 12 HOURS...BOTH THE ECMWF/GFS HAVE BEEN MORE STABLE WITH A SFC
LOW TRACKING ACROSS SRN MN ON MONDAY. IT STILL LOOKS WARM ENOUGH
MONDAY WITH TEMPERATURES/DEWPOINTS UP IN THE MID 30S SOUTH OF I-94
TO LEAD TO A RA/SN MIX ON MONDAY BEFORE THE LOW LEVELS COOL ENOUGH
FOR ALL SNOW BY MONDAY EVENING. GIVEN THE INTENSIFICATION THIS LOW
GOES THROUGH...IT DOES NOT MOVE VERY FAR...WITH BOTH THE ECMWF AND
GFS SHOWING A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW IMPACTING
THE AREA MOST OF MONDAY NIGHT THROUGH TUESDAY NIGHT BEFORE SLOWLY
TAPERING OFF ON WEDNESDAY. BECAUSE IT IS SLOWEST...THE ECMWF IS ALSO
THE MOST BULLISH WITH QPF...WITH A HEALTHY SWATH OF AROUND 0.75"
ROTATING AROUND SE MN...WHICH WOULD TRANSLATE TO 6-8 INCHES OF
SNOW...OF COURSE THIS FALLS OVER THE COURSE OF ABOUT 48 HOURS.
ALTHOUGH THE SNOW MAY TAPER OFF ON WEDNESDAY...IT WILL BE REPLACED
BY BLOWING SNOW ISSUES AS NW WINDS START CRANKING IN RESPONSE TO THE
SFC LOW DIPPING UNDER 970 MB OVER THE GREAT LAKES. AT THIS
POINT...STILL WAY TO EARLY TO GET TOO EXCITED ABOUT POTENTIAL SNOW
TOTALS/IMPACTS...BUT GIVEN INCREASED TRAVEL THE FIRST HALF OF NEXT
WEEK...THIS CERTAINLY IS SOMETHING THAT BEARS WATCHING. WILL ALSO
ADD A MENTION FOR THE POTENTIAL FOR ACCUMULATING SNOW NEXT WEEK IN
THE HWO.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1132 AM CST WED DEC 17 2014

SCATTERED FLURRIES REMAIN IN PLACE OVER EASTERN MN AND WESTERN
WI...ASSOCIATED WITH AN UPPER LOW OVER THE WESTERN GREAT LAKES.
THIS FEATURE IS DRIFTING EASTWARD...BUT ENOUGH LOW LEVEL MOISTURE
AND FORCING REMAIN FOR SCATTERED MVFR CIGS AND FLURRIES THROUGH
THE REST OF THE AFTERNOON. LOW CLOUDS SHOULD MAINLY DISSIPATE BY
TONIGHT...WITH VFR CONDITIONS AND LIGHT WINDS EXPECTED AT MOST
TERMINALS THROUGH THE END OF THE PERIOD. HOWEVER...SCATTERED LOW
CLOUDS CAN NOT BE RULED OUT TONIGHT THROUGH THURSDAY MORNING SINCE
DECENT LOW LEVEL MOISTURE REMAINS IN PLACE.

KMSP...PERIODS OF MVFR CIGS ARE POSSIBLE THE REST OF THE AFTERNOON
AS SCATTERED/BROKEN LOW CLOUDS MOVE THROUGH WITH A FEW FLURRIES.
MOST LOW CLOUDS SHOULD DISSIPATE BY THE EARLY EVENING...WITH VFR
CONDITIONS EXPECTED TO PREVAIL FROM THE EVENING THROUGH THE
REMAINDER OF THE PERIOD.

/OUTLOOK FOR KMSP/
THU...VFR. WINDS VARIABLE LESS THAN 5 KTS.
FRI...VFR. WINDS SSE 5 KTS.
SAT...VFR. WINDS SSE 5 KTS.

&&

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

$$

SHORT TERM...JLT
LONG TERM...MPG
AVIATION...ADL



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