Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 231142
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
542 AM CST FRI JAN 23 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST FRI JAN 23 2015

SHORT TERM CONCERN REMAINS THE THREAT OF FREEZING RAIN/SLEET MOVING
ACROSS THE NORTHERN AND EASTERN CWA MAINLY THROUGH THIS MORNING.

CURRENT RADAR TRENDS INDICATE MODELS MAY BE DOWNPLAYING EXTENT OF
FREEZING RAIN THREAT.  WILL FOLLOW A COMBO RAP ISENTROPIC
ANALYSIS (290K/295K LAYERS) AND HRRR TREND FOR POPS THIS AM.
STILL LOOKS THE BEST THREAT REMAINS ALONG AND NORTH OF THE I94
CORRIDOR. WILL LET THE ADV EXPIRE TO THE FAR WEST THROUGH 15Z AND
IN THE EAST BY 18Z. ROAD TEMPERATURE ARE CURRENTLY AROUND 30F IN
THE NORTHERN CWA AND COOLER INTO THE SOUTHERN PORTION OF THE AREA.
SURFACE DEWPTS ARE IN THE LOWER 20S TO THE SOUTH WILL BOTH HELP
AND HINDER FREEZING RAIN THREAT. MAY TAKE SOME TIME TO SATURATE
THE FARTHER SOUTH THE AREA OF PRECIPITATION MOVES THIS MORNING. IF
IT DOES PRECIPITATE...SOME COOLING FROM THE DRIER AIR WILL ENHANCE
THE FREEZING RAIN THREAT ON UNTREATED ROADS/BRIDGES.

TEMPERATURES SHOULD WARM ABOVE FREEZING THROUGH NOON MOST AREAS
ENDING THE FREEZING RAIN THREAT.  THIS SYSTEM EXITS TO THE EAST BY
THIS EVENING WITH CLOUDS REMAINING THROUGH THE NIGHT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 421 AM CST FRI JAN 23 2015

THE LONG TERM BEGINS SATURDAY TRANQUIL AROUND HERE...BUT A STRONG
NOR EASTER WILL BE PUSHING UP THE EAST COAST WHILE A RIDGE BUILDS
UP THE WEST COAST. BOTH WILL IMPACT THE CLIPPER SET TO DIVE INTO
THE UPPER MIDWEST SATURDAY NIGHT. MODELS HAVE TRENDED SHARPER WITH
THE WAVE WHICH RESULTS IN A WESTWARD SHIFT SIMILAR TO WHAT WAS
SEEN WEDNESDAY NIGHT. GIVEN THE SYNOPTIC SET UP...THIS IS THE
PREFERRED TREND. 00Z NAM WAS FLATTEST AND MUCH FURTHER EAST THAN
THE REST OF THE GUIDANCE AND WAS IGNORED. THE GFS/CANADIAN SEEM
LIKE THE BEST COMPROMISE WITH THE ECMWF A BIT TOO FAST AND
CONSIDERABLY LIGHTER WITH ITS PRECIP. 06Z NAM HAS TRENDED FURTHER
WEST CLOSER TO THE 00Z GFS AND CANADIAN. AT THIS STAGE...IT IS
UNLIKELY THE TRACK WILL SHIFT SIGNIFICANTLY EAST...BUT IT COULD
STILL TREND SLIGHTLY WEST.

THE TRACK OF THE LOW WILL PLAY A SIGNIFICANT ROLE IN WHO SEES THE
MOST ACCUMULATION. A GOOD BAND OF SNOW WILL SET UP ALONG AND JUST
EAST OF THE LOW...WITH SOME POTENTIAL FOR DRY SLOTTING ON THE WEST
SIDE. IT WILL BE A QUICK MOVER...SO ONLY EXPECTING ABOUT 6-9 HOURS
OF ACCUMULATING SNOWFALL. A GENERAL 2-4 INCHES APPEAR LIKELY
WITHIN THE HEART OF THE BAND WITH AMOUNTS GRADUALLY TAPERING OFF
TO THE EAST AND QUICKLY TAPERING OFF TO THE WEST. CURRENTLY...THE
HEAVIEST AXIS OF SNOW IS FORECAST TO SET UP FROM NORTHWEST MN TO
EAST CENTRAL MN AND SOUTHWEST WI. FLURRIES MAY PERSIST INTO
SUNDAY MORNING BUT A SURFACE RIDGE AXIS WILL BUILD IN SUNDAY
AFTERNOON.

ANOTHER CLIPPER WILL BRING A BAND OF LIGHT SNOW ACROSS MN SUNDAY
NIGHT AND INTO WISCONSIN BY MONDAY. THIS WILL BE A SLOWER MOVER
SINCE THE FIRST CLIPPER WILL BE DEVELOPING OFF THE EAST COAST. A
PROLONGED PERIOD OF LIGHT SNOW OR FLURRIES COULD DEVELOP OVER THE
EASTERN AREAS DURING THIS TIME. ACCUMULATIONS WILL BE LIGHTER THAN
WITH THE FIRST SYSTEM.

A PATTERN SHIFT WILL TAKE PLACE TUESDAY AND WEDNESDAY WITH THE
RIDGE BUCKLING TO THE NORTHEAST. A SHOT OF WARMTH WILL SURGE INTO
THE UPPER MIDWEST THANKS TO A 50+ KT 850 MB JET BRINGING +10 TO
+13C AIR IN. GUIDANCE IS WAY TOO COLD IN SUCH A PATTERN...AND
NUDGED TEMPS UP SEVERAL DEGREES. MAY CRACK 50+ ACROSS WRN MN AND
MID TO POSSIBLY UPPER 40S FURTHER EAST.

COLD FRONT WILL DROP SOUTH FOR LATE WEEK AS THE PATTERN SHIFTS
TOWARD SOMETHING MORE COMMON DURING THE LAST YEAR. LUCKILY FOR
US...THE COLDEST SURGE OF ARCTIC AIR WILL ROTATE EAST INTO NEW
ENGLAND AND GIVE US A GLANCING BLOW. EVEN WITH THIS...TEMPS WILL
STILL REMAIN NEAR AVERAGE THURSDAY AND FRIDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 527 AM CST FRI JAN 23 2015

CURRENT RADAR AND MODEL TRENDS CONTINUE TO DROP BAND OF LIGHT
FREEZING RAIN AND SOME SLEET SOUTHEAST OVER THE NORTHEAST CWA
THROUGH 18Z. BEST CHANCES OF THIS OCCURRING AT KSTC-KRNH AND KEAU
THROUGH 18Z. KMSP WILL BE ON THE EDGE OF THE ACTIVITY...BUT STILL
THREAT REMAINS IN THE 14Z-17Z PERIOD. AREA DROPS SOUTHEAST AND
EXITS BY THE AFTERNOON.

NEXT PROBLEM IS THE MVFR CIG THREAT DEVELOPING LATER THIS
AFTERNOON AND TONIGHT. FOLLOWED A SLOWER SREF PROGRESSION FOR
THIS. SHALLOW RH LAYER ON BUFKIT PROFILES SO THERE IS A CHANCE OF
JUST SCT LOWER CLOUDS INTO THE EVENING. WILL HAVE TO MONITOR CLOUD
TRENDS AS ANY REAL LOW CLOUDS RESIDE ALONG THE MN/CANADIAN BORDER.
HIGHER CONFIDENCE IN LOW END MVFR CIGS DEVELOPING INTO THE
EVENING. SURFACE WINDS SOUTHWEST BECOMING MORE WEST/NORTHWEST WITH
PASSAGE OF SURFACE TROUGH TODAY.

KMSP...

STILL OUR CONFIDENCE IS NOT 100% FOR FREEZING RAIN OR SLEET
OCCURRING AT THE AIRPORT. WE CONTINUE TO THINK THE CHANCE IS HIGH
ENOUGH TO INCLUDE THE FREEZING PRECIP IN THE TAF. ANY PRECIP THAT
DOES OCCUR WILL BE LIGHT AND MAY NOT MEASURE. RUNWAY TEMPERATURES
REMAIN 28-30 WITH AIR TEMPERATURE AROUND 30. SOME SLIGHT UPWARD
TREND IN THESE READING SWILL OCCUR THIS MORNING. BUT WILL BE
CRITICAL WHEN GREATEST PSPN THREAT OCCURS...WHICH REMAINS
14Z-17Z FOR KMSP. CONTINUE TO EXPECT MVFR CIGS DEVELOPING LATER
THIS AFTERNOON BEHIND THE TROUGH PASSAGE. THESE LOWER END MVFR
CIGS SHOULD CONTINUE THROUGH THE NIGHT INTO SATURDAY.

/OUTLOOK FOR KMSP/
SATURDAY NIGHT...BECOMING MVFR. CHC IFR CIGS/VSBYS -SN MAINLY
AFTER 06Z SUN. WIND W 5-10 KTS.
SUNDAY...MVFR WITH -SN/IFR POSSIBLE. WIND NW 10G20 KTS.
MONDAY...VFR. WIND SW 5-10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ043>045-
     049>053-061-063.

     WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ041-
     042-048.

WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023-
     025-027.

&&

$$

SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...DWE


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