Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 261131
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
531 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 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 514 AM CST WED NOV 26 2014

SINCE 3 AM...AN ENHANCED AREA OF SNOW HAD DEVELOPED ACROSS SC MN
WHICH HAS MOVED NORTHWARD INTO PORTIONS OF EC MN. OTHER AREAS OF
SW MN HAVE DETERIORATED AS BOTH THE NEXT DISTURBANCE MOVING SE
ACROSS WC MN AND THE DEPARTING SFC LOW CONVERGE. BASED ON THE
LATEST MODEL GUIDANCE AND SFC OBS/REFLECTIVITY PATTERN...THE
ENHANCED AREA IN SC MN WILL LIKELY PRODUCE 1/2 TO LOCALLY 3/4 INCH
PER HR SNOWFALL RATES WITH VSBYS LESS THAN 1/2SM AT TIMES. ONLY
KRWF/KMSP WILL BE AFFECTED BY THESE HIGHER RATES...BUT SHOULD ONLY
LAST 2 TO 3 HRS AS THE MAIN UPPER SUPPORT MOVES SE OF OUR REGION.
CONFIDENCE IS HIGH FOR KRWF TO CONTINUE WITH IFR/LIFR THRU
15-18Z...WITH MVFR DURING THE AFTN. KAXN/KSTC/KRNH WILL LIKELY BE
ON THE EDGE OF IFR VSBY IN SN...BUT CIGS SHOULD REMAIN AOA 1.5K.
CONFIDENCE IN THESE AREAS REMAIN MODERATE. KEAU WILL LIKELY REMAIN
VFR UNTIL THIS AFTN. SFC WINDS INITIALLY WILL BE FROM THE
N/NE...THEN BACK TO THE N/NW DURING THE AFTN. SPDS WILL HOLD IN
THE 10-15 KT RANGE...WITH OCCASIONAL GUSTS ABV 20 KTS IN WC/SW MN.

KMSP...

CONFIDENCE HAS INCREASED TO SUPPORT IFR CIGS/VSBYS DURING THE NEXT
6 HRS. CONFIDENCE REMAINS LOW ON SNOWFALL RATES OF 3/4 TO 1 INCH
PER HR. THE BEST SCENARIO IS 1/2 INCH PER HR BETWEEN 13-17Z AS
BOTH THE DEEPER MOISTURE AND LIFT ARE PRESENT. THERE REMAINS A
POSSIBILITY OF A SECONDARY BAND OF -SN TO CONTINUE ACROSS THE
AIRPORT GROUNDS BETWEEN 18-21Z...BUT CONFIDENCE REMAINS LOW WITH A
FASTER SCENARIO OF MVFR/VFR CONDS DEVELOPING. WINDS WILL REMAIN
FROM THE NE THIS MORNING...WITH WINDS BACKING TO THE NNW/N DURING
THE AFTN AND INCREASING TO 10 KTS.

/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...JLT



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