Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 261025
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
425 AM CST WED NOV 26 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CST WED NOV 26 2014

THE MAIN CONCERN TODAY IS WHETHER A DRY LAYER BLW 5K ACROSS SE/EC
MN AND INTO WC WI WILL ERODE FASTER DUE TO ANTICIPATED DENDRITIC
ZONE ENHANCEMENT EXPECTED IN THE NEXT SEVERAL HRS. HOWEVER...
MODELS HOLD ONTO THE DRIER LAYER LONGER INTO THE MORNING...OR
UNTIL THE NORTHERN SHORTWAVE AND ASSOCIATED FRONTOGENETIC FORCING
MOVES INTO THE REGION BY LATE MORNING/NOON.

MESOSCALE MODELS HAVE TRENDED FOR THE HEAVIER BANDS OF SNOW TO
HOLD FROM THE SW METRO AREA...SOUTH/SSW TOWARD MKT AND FRM. A
SECONDARY BAND DEVELOPS AFTER 18Z ALONG THE LINE FROM NW WI...SW
TO THE TWIN CITIES WHICH AGAIN IS ASSOCIATED WITH THE SECONDARY
SHORTWAVE.

DUE TO SOME UNCERTAINTIES OF WHERE THIS DRY SLOT HOLDS WILL
CONTINUE WITH THE SAME ADVISORY AREA WHERE LOCALLY 3 TO 5 INCHES
WILL FALL BY EARLY-MID AFTERNOON. HIGHEST CONFIDENCE OF LOCALLY 3
TO 5 INCHES WILL FALL FROM MKT...SOUTHWARD TO THE IOWA BORDER AS
BOTH THE STRONGER LIFT AND DEEPER MOISTURE RESIDES. AFT
21Z...THERE WILL BE A SHARP CUTOFF FROM NW TO SE AS THE MAIN
SHORTWAVE MOVES THRU THE UPPER MIDWEST. MOST AREAS WILL TAPER OFF
TO FLURRIES OR LIGHT SNOW IN SE/SC MN AND WC WI BY EARLY EVENING.

SFC WINDS WILL BECOME GUSTY IN WC/SW MN AS THE SFC LOW MOVES INTO
SOUTHERN IOWA. THERE WILL BE LOCALIZED LOWER SFC VSBY DUE TO
BLOWING SNOW. BUT NOT EXPECTING BLIZZARD CONDS. THE STRONGEST
WINDS WILL OCCUR SW OF MPX CWA. WIND CHILL VALUES WILL LIKELY FALL
WELL BLW ZERO OVERNIGHT AS TEMPS FALL INTO THE SINGLE DIGITS BLW
ZERO...TO AROUND 5 ABV ZERO.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 318 AM CST WED NOV 26 2014

A FAIRLY PROGRESSIVE PATTERN IS EXPECTED TO REMAIN IN PLACE
STARTING ON THANKSGIVING AND CONTINUING INTO EARLY NEXT WEEK...
BOTH IN TERMS OF A ROLLER COASTER OF TEMPERATURES AND IN
OCCASIONAL QUICK-HITTING MINOR WINTER WEATHER EVENTS.

A STRONG SURGE OF COLD AIR WILL ACCOMPANY HIGH PRESSURE SLIDING
ACROSS THE REGION DURING THE DAY ON THANKSGIVING...BUT THIS AREA
OF HIGH PRESSURE WILL QUICKLY MOVE OFF TO THE SOUTHEAST THURSDAY
NIGHT IN ADVANCE OF AN ORGANIZING AREA OF LOW PRESSURE OVER THE
PAC NW. THIS LOW WILL GRADUALLY DRIVE SE THEN E OVER THE NRN
PLAINS AND UPR MISS RIVER VALLEY FRIDAY THROUGH SATURDAY. IN
ADVANCE OF THIS LOW...STRONG WARM ADVECTION COMBINED WITH SURGING
SLY MOISTURE INTO THE REGION WILL BE ABLE TO PRODUCE AT LEAST A
COUPLE INCHES OF ACCUMULATING SNOW FOR MAINLY NRN AND ERN PORTIONS
OF THE WFO MPX CWFA FOR THU NIGHT THROUGH FRI. HOW MUCH AND WHEN
SNOW FALLS WILL BE DEPENDENT ON THE AMOUNT OF MOISTURE AND WARM
AIR BEING BROUGHT INTO THE REGION...BUT ATTM THERE IS NO REASON TO
BELIEVE THERE WILL BE ANYTHING MORE THAN MINOR ACCUMULATIONS. THAT
SAID...THERE IS ALSO THE POSSIBILITY OF SOME MIXED WINTRY
PRECIPITATION FOR SRN AND SERN PORTIONS OF THE COVERAGE AREA ON
THE BACKSIDE OF THIS SYSTEM FOR FRI INTO FRI NIGHT. AGAIN...NOT
LOOKING FOR MUCH IN THE WAY OF ICING BUT WITH SOME WARMER AIR
ALOFT...IT IS NOT UNREASONABLE TO POTENTIALLY HAVE SOME GLAZING
BEFORE THE PRECIPITATION ENDS. THIS SYSTEM FINALLY EJECTS OFF TO
THE EAST SAT NIGHT INTO SUN...WITH ANY REMAINING SNOWFALL FROM
THIS SYSTEM FRI NIGHT THROUGH SAT REMAINING JUST N OF THE MPX
CWFA. THE WARM AIR REMAINS IN PLACE THRU SAT...THEN THE ASSOCIATED
CDFNT PUSHES THRU EARLY SUN... BRINGING A RETURN OF MUCH COLDER
AIR TO THE REGION FOR THE START OF NEXT WEEK. ANOTHER LOW PRES
SYSTEM LOOKS TO IMPACT THE AREA FOR TUE INTO WED...BUT CONFIDENCE
IS LOW ON THERE ACTUALLY BEING MEASURABLE PRECIP SO HAVE CAPPED
POPS AT 20 PERCENT FOR TUE AND TUE NIGHT. A BRIEF WARMUP FOR TUE
IS EXPECTED WITH THIS SYSTEM...BUT NOT ENOUGH TO PRODUCE A P-TYPE
TO ANYTHING OTHER THAN -SN. ANOTHER COLD SURGE WILL FOLLOW THIS
SYSTEM FOR THE LATTER HALF OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1139 PM CST TUE NOV 25 2014

CONFIDENCE HAS INCREASED FROM THE LAST SET OF TAFS REGARDING THE
SNOW FOR WEDNESDAY. IT HAS ALREADY BEGUN PUSHING INTO THE RWF
AREA AND WILL TAKE ANOTHER HOUR OR TWO TO REACH AXN. EASTWARD
PROGRESSION WILL SLOW OVERNIGHT...THEN BEGIN TO DEVELOP FURTHER
EAST INTO THE TWIN CITIES METRO AND STC SHORTLY BEFORE DAWN.
INVERTED TROUGH SHOULD CONCENTRATE MUCH OF THE SNOW DURING THE
DAYTIME IN AN AREA FROM STC TO RWF...MKT...AND MSP. SNOW RATES
WILL INCREASE BETWEEN 12-18Z IN THIS AREA WHERE 1/2 TO 1 INCH PER
HOUR RATES ARE POSSIBLE FOR A TIME. THE SNOW WILL TAPER OFF DURING
THE AFTERNOON FROM WEST TO EAST. ONLY LOOKING FOR A 2 TO 4 HOUR
WINDOW OF LIGHT SNOW ACROSS WRN WI...MAINLY DURING THE MID
AFTERNOON TO EARLY EVENING.

KMSP...LIGHT SNOW LOOKS LIKE IT WILL BEGIN AROUND 12Z...AND COULD
BECOME MORE INTENSE BETWEEN 14-19Z WHEN SNOWFALL RATES OF 1/2 TO
1 INCH PER HOUR AND IFR/LIFR CONDITIONS ARE POSSIBLE. THE SNOW
WILL TAPER OFF MID AFTERNOON WITH VFR CONDITIONS EXPECTED AFTER
MID EVENING.

/OUTLOOK FOR KMSP/
FRI...CHC MVFR AND -SN. WINDS SE 5 KTS.
SAT...CHC MVFR. WINDS N 10 KTS.
SUN...VFR. WINDS NW 10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ059-
     060-062-068>070-076-077-084-085-093.

     WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ054-056>058-
     064>067-073>075-082-083-091-092.

WI...NONE.
&&

$$

SHORT TERM...JLT
LONG TERM...JPC
AVIATION...BORGHOFF






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