Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 191803 AAC
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
ISSUED BY NATIONAL WEATHER SERVICE DULUTH MN
1203 PM CST WED NOV 19 2014

.UPDATE...
ISSUED AT 1203 PM CST WED NOV 19 2014

UPDATED AVIATION DISCUSSION BELOW FOR 18Z TAF ISSUANCE.

UPDATE ISSUED AT 1025 AM CST WED NOV 19 2014

BLUSTERY/COLD CONDITIONS WITH OCCASIONAL LIGHT SNOW/FLURRIES WILL
PERSIST INTO LATE AFTERNOON. OVERALL..THE FORECAST IS GENERALLY ON
TRACK THIS MORNING WITH ONLY A FEW MINOR TWEAKS TO ACCOUNT FOR
SHORT TERM TRENDS.

SHORT WAVE TROF AXIS HAS MOVED SOUTHEAST OF THE AREA LATE THIS
MORNING..WITH GUSTY NORTHWEST WINDS AND SCATTERED PATCHES OF
LIGHT SNOW/FLURRIES IN ITS WAKE. STEEP LOW LEVEL LAPSE RATES WILL
PERSIST FOR MOST OF THE DAY..AND THIS WILL ACT TO KEEP WIND GUSTS
IN THE 23-28 MPH RANGE AND SNOW SHOWERS/FLURRIES GOING IN SOME
AREAS WELL INTO THE AFTERNOON. HOWEVER..VERY LITTLE IN THE WAY OF
ACCUMULATION IS EXPECTED.

AREAS OF BLOWING AND DRIFTING SNOW WILL CONTINUE AS WELL..MOST
WIDESPREAD ACROSS THE WESTERN AND SOUTHERN SECTIONS OF THE MPX
CWA. WIND SPEEDS ARE NOT EXPECTED TO GET TOO OUT OF HAND..SO
SIGNIFICANT VISIBILITY RESTRICTIONS SHOULD NOT BE WIDESPREAD.
WE RAISED TEMPS A FEW DEGREES FOR THE REMAINDER OF THE DAY BASED
ON CURRENT OBS AND SHORT TERM TRENDS..BUT OVERALL CHANGES TO THE
FORECAST THIS MORNING WERE MINOR.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CST WED NOV 19 2014

SHORT TERM CONCERNS INCLUDE TIMING OF SNOW EXITING TO THE EAST THIS
MORNING AND BLOWING SNOW THREAT TODAY.  THEN EXTENT OF CLEARING
OVERNIGHT AND LOW TEMPERATURE POTENTIAL.

WATER VAPOR SATELLITE IMAGERY SHOWING DECENT SHORT WAVE MOVING
ACROSS SOUTHERN MN THIS MORNING.  SURFACE ANALYSIS HAS THE COLD
FRONT PUSHING INTO CENTRAL MN AT 08Z.  THIS FRONT IS PROGGED TO EXIT
INTO WISCONSIN AFTER 12Z.  THE LIGHT SNOW OVER AHEAD OF THE FRONT
SHOULD MOVE INTO WESTERN WISCONSIN THROUGH 12Z AS WELL.  THIS MAY
LINGER THROUGH ABOUT MID MORNING THERE.  HIGH SLR SNOWFALL OVER THE
AREA...HAS YIELDED AROUND 1/2 TO 1 INCH OF FLUFFY SNOW.  THOUGHT NOW
IS THAT THIS WAS MAINLY INTO CENTRAL AND EASTERN MN OVERNIGHT.  THE
STRONGEST WINDS ARE FORECAST TO REMAIN OVER WESTERN INTO SOUTH
CENTRAL MN.  THE GREATEST PRESSURE RISES ARE NOW DROPPING ACROSS
SOUTHWEST MN INTO NORTHWEST IOWA.  THIS SHOULD PROHIBIT SIGNIFICANT
GUST POTENTIAL INTO SOUTHERN MN.  STRONG CAA AND TIGHTENING
PRESSURE GRADIENT WILL STILL GENERATE GUSTS TO AT LEAST 35 MPH INTO
THE DAY.  BLOWING SNOW COULD BECOME A GREATER THREAT IF WINDS BECOME
STRONGER THAN ALREADY FORECAST. WILL HAVE TO MONITOR CONDITIONS INTO
THE MORNING FOR POSSIBLE ADVISORY.

CLOUDS AND FLURRIES WILL REMAIN OVER THE CWA OR MUCH OF THE DAY.  WE
COULD SEE SOME EROSION IN THE CLOUDS TO THE SOUTHWEST...BUT MOSTLY
CLOUDY CONDITIONS ARE ANTICIPATED WITH CAA AND WEAK CYCLONIC FLOW TO
THE EAST.  TEMPERATURES WILL PROBABLY SETTLE OUT AROUND 20 DEGREES FOR
HIGHS OVER MUCH OF THE CWA TODAY.

MODELS SUGGEST LOW LEVEL HUMIDITY TO REMAIN HIGH OVER THE EASTERN
HALF OF THE CWA INTO TONIGHT.  THE SURFACE RIDGE DROPS SOUTHEAST
ACROSS EASTERN SOUTH DAKOTA AND IOWA TONIGHT INTO THURSDAY...SO
WILL TREND CLOUDIER CONDITIONS TO THE EAST.  LOWS TONIGHT WILL BE
DIFFICULT TO FORECAST WITH UNCERTAINTY IN CLOUD COVER.  WILL FOLLOW
MORE OF AN ALL BLEND APPROACH TO TEMPERATURES FOR NOW.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 400 AM CST WED NOV 19 2014

LONG TERM FORECAST CONCENTRATIONS ARE CENTERED AROUND CHANCES FOR
FREEZING PRECIPITATION OVER THE WEEKEND...AND THEN ON A
POTENTIALLY IMPACTFUL WINTER SYSTEM FOR MONDAY.

THE PERIOD STARTS OUT ON A FAIRLY BENIGN NOTE ON THURSDAY...WITH
SURFACE HIGH PRESSURE IN CONTROL. IT WILL BE ANOTHER CHILLY DAY
HOWEVER...WITH 925 MB TEMPS AROUND -14C AND WEAK COLD AIR
ADVECTION CONTRIBUTING TO HIGHS IN THE LOW/MID TEENS. CLEAR SKIES
AND THE CONTINUED INFLUENCE OF SFC HIGH PRESSURE WILL LIKELY YIELD
SUBZERO TEMPS ACROSS MUCH OF THE FORECAST AREA ON THURSDAY
NIGHT...WITH POSSIBLY ONLY A FEW LOCATIONS IN WEST AND SOUTH
CENTRAL MN HOLDING A COUPLE DEGREES ON THE POSITIVE SIDE OF ZERO.

FRIDAY BRINGS THE RETURN TO SOUTHERLY FLOW AS SURFACE HIGH
PRESSURE SLIDES EAST/SOUTHEAST OF THE AREA AND TROUGHING BEGINS TO
APPROACH FROM THE WEST/SOUTHWEST. WEAK WARM AIR ADVECTION DEVELOPS
AHEAD OF AN ADVANCING TROUGH. BOTH 19.00Z GFS AND ECMWF MODELS
CAME IN SLOWER...DRIER AND FARTHER EAST FOR FRIDAY NIGHT...AND
THEREFORE MEASURABLE PRECIP CHANCES WERE REMOVED UNTIL AFTER
DAYBREAK SATURDAY. CHANCES ON SATURDAY INTO SATURDAY NIGHT LOOK TO
BE CONFINED TO AREAS EAST OF THE INTERSTATE 35 CORRIDOR /PRIMARILY
WI/. SURFACE TEMPS SHOULD BE PRIMARILY ABOVE 32 DEGREES THROUGH
MOST OF SATURDAY AND SATURDAY NIGHT GIVEN THE LOW LEVEL WARM AIR
ADVECTION AND CLOUD COVER...SO THE FREEZING RAIN THREAT APPEARS
LIMITED THROUGH THEN. REGARDING HIGH TEMPS...THE WEEKEND WILL BE A
WELCOMED RETURN FOR MANY TO NEAR NORMAL HIGHS IN THE 30S.

ON SUNDAY...THE TROUGH LIFTS TO SOUTHERN LAKE MICHIGAN...AND
DEEPENS TO CIRCA 985 MB. FREEZING/MIXED PRECIPITATION CONCERNS THEN
INCREASE FOR SUNDAY...ALTHOUGH THERE IS A DECENT CHANCE THAT WE
COULD BE DRY SLOTTED FOR MUCH OF THE DAY.

SUNDAY NIGHT AND MONDAY REALLY LOOKS TO BE THE TIME PERIOD OF
UTMOST CONCERN...GIVEN BOTH GFS AND ECMWF MODELS CRANK NORTHWEST
WINDS UP TO 25-35 MPH /SUSTAINED/ IN CONJUNCTION WITH DEFORMATION
SNOW TAKING PLACE AS THE AFOREMENTIONED LOW DEEPENS FURTHER AND
PIVOTS NORTH-NORTHWEST TO LAKE SUPERIOR. WILL DEFINITELY NEED TO
MONITOR FOR THE BLOWING SNOW POTENTIAL...WITH NOTABLE SNOW ACCUMS
ALSO A POSSIBILITY. HOWEVER...MODELS HAVE LACKED RUN TO RUN
CONSISTENCY WITH THEIR HANDLING OF THE KEY PLAYER...THE STRENGTH
OF THE NORTHERN STREAM SHORTWAVE...SO HAVE KEPT SNOW CHANCES IN
THE LOW CHANCE CATEGORY AT THIS POINT.

BY TUESDAY...WEATHER CONDITIONS SHOW IMPROVEMENT...WITH MODELS
INDICATING SURFACE HIGH PRESSURE BUILDING IN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1203 PM CST WED NOV 19 2014

SHORT WAVE TROF AND ASSOCIATED COLD FRONT HAVE MOVED EAST OF THE
AREA AS OF MIDDAY..AND THE STRONGEST PRESSURE RISES HAVE
TRANSLATED SOUTHWARD INTO IOWA/MISSOURI. HOWEVER..STEEP LOW LEVEL
LAPSE RATES AND A RATHER STRONG PRESSURE GRADIENT REMAIN IN PLACE
ACROSS THE ENTIRE AREA BEHIND THE FRONT. THIS CONTINUES TO SUPPORT
WIDESPREAD LIGHT SNOW/FLURRIES..AS WELL AS SOME AREAS OF BLOWING
SNOW. IN GENERAL..VFR CEILINGS/VISIBILITIES ARE EXPECTED..BUT
BRIEF PERIODS OF 3-5 MILE VISIBILITIES/MVFR CEILINGS ARE POSSIBLE
THROUGH THE AFTERNOON AS A FEW STRONGER SNOW SHOWERS DEVELOP WITH
STRONG NEAR-SURFACE INSTABILITY AND LAPSE RATES. WINDS SHOULD
DECREASE AND BACK TO MORE WESTERLY DIRECTION 23-03Z WITH GUSTINESS
SUBSIDING TO LESS THAN 15 KNOTS. WINDS MAY INCREASE MID MORNING
THURSDAY AS PRESSURE GRADIENT REMAINS SUFFICIENTLY STRONG ALONG
WITH STEEP LOW LEVEL LAPSE RATES THAT SHOULD ALLOW SOME MIXING
INTO STRONGER FLOW JUST OFF THE SURFACE.

KMSP...FLURRIES AND WNW WINDS GUSTING TO 25-30 KT WILL PERSIST FOR
MUCH OF THE AFTERNOON..AND THERE IS A SMALL CHANCE FOR SHORT
WINDOWS OF MVFR CEILINGS IN SNOW SHOWERS. WINDS EXPECTED TO SLOWLY DIMINISH
THIS EVENING..BUT SOME GUSTS TO AROUND 20 KT ARE STILL POSSIBLE
UNTIL 04-05Z TIME FRAME. WIND DIRECTION SHOULD REMAIN NEARLY
CONSTANT FROM AROUND 300 DEGREES UNTIL SOMETIME LATE THIS EVENING
WHEN THEY BECOME MORE WESTERLY.

/OUTLOOK FOR KMSP/

THUR NIGHT...VFR. WINDS LIGHT WNW BECOMING LIGHT SE
FRI...VFR. WINDS SSE 10-15 KT.
SAT...MVFR POSSIBLE AFTER 16Z. WINDS S/SW 10-20KT.
SUN...MVFR/IFR. CHANCE OF FZDZ OR RA. WINDS SE 10 KT.

&&

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

$$







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