Quantitative Precipitation Forecast
Issued by NWS

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
000
FOUS11 KWBC 020856
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
356 AM EST TUE FEB 02 2016

VALID 12Z TUE FEB 02 2016 - 12Z FRI FEB 05 2016


DAYS 1 THROUGH 3...

...CENTRAL PLAINS/UPPER MS VALLEY/UPPER GREAT LAKES...

A MAJOR SNOWSTORM OVER THE CENTRAL PLAINS IS EXPECTED TO PROGRESS
ACROSS PORTIONS OF THE UPPER MS VALLEY AND GREAT LAKES THRU TUE
NIGHT. CYCLOGENESIS TAKING PLACE OVER SOUTHERN/SOUTHEAST COLORADO.
HAS LED TO LOW-MID LEVEL FRONTOGENESIS AND 850-700 MB WARM/MOIST
ADVECTION...RESULTING IN HEAVY SNOWS TO THE NORTH AND WEST OF THE
850 MB LOW WHILE IT LIFTS NORTHEASTWARD THROUGH THE CENTRAL PLAINS
AND UPPER MISSISSIPPI VALLEY...AND THEN INTO THE UPPER GREAT LAKES
REGION TUE NIGHT.  ALONG THE 850 MB LOW TRACK THE MODELS FCST
TEMPERATURES TO RISE ABOVE FREEZING...WHICH PRESENTS A
PRECIPITATION TYPE TRANSITION AND REDUCED AMOUNTS FROM SOUTHEAST
NEBRASKA TO SOUTHEAST IOWA AND SOUTHERN WI/CENTRAL MI.

THE MULTI-MODEL AGREEMENT ON AN ADDITIONAL THREE FOURTHS OF AN
INCH TO AN INCH  LIQUID EQUIVALENT QPF IN THE COLD SECTOR SUPPORTS
POTENTIAL FOR 6 TO 12 INCHES OF SNOW IN THE AREA OF HEAVIEST SNOW
FROM NORTHEASTERN NEBRASKA AND NORTHWEST IOWA...EXTENDING
NORTHEAST TO THE UP OF MI.

THE 00Z MODEL CYCLE SAW CONVERGENCE OF LOW TRACKS...SO THERE IS
GOOD AGREEMENT ON THE AXIS/ORIENTATION OF THE AREAS OF HEAVY SNOW.
 THE GEFS AND ECMWF ENSEMBLE MEANS CLUSTER WELL WITH THE GFS/ECMWF
LOW TRACKS...SO THESE SOLUTIONS WERE GIVEN EQUAL WEIGHTING FOR QPF
AND TEMPERATURE PROFILES.  LAKE ENHANCEMENT KICKS IN TOWARDS WED
MORNING AND CONTINUES DURING THE DAY OFF LAKE SUPERIOR...ADDING
ADDITIONAL SNOW IN AREAS OF LEE SHORE WIND CONVERGENCE IN THE UP
OF MI.

...PACIFIC NORTHWEST/NORTHERN ROCKIES...

LIGHT SNOW SHOWERS SHOULD CONTINUE OVER THE HIGHER ELEVATIONS OF
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES ON DAY 1...WITH THE
DEPARTURE OF THE UPPER TROUGH EAST TO THE PLAINS AND APPROACH OF
THE UPSTREAM UPPER RIDGE. MORE SIGNIFICANT SNOW ARE EXPECTED DAY 2
AS THE NEXT UPPER TROUGH APPROACHES THE REGION...WITH THE GEFS
STANDARDIZED ANOMALIES INDICATING 850-700 MB MOISTURE FLUX
ANOMALIES OF 1-2 STD DEVIATIONS ABV NORMAL WED AFTERNOON EVENING
IN WESTERN WA/OR.  LOW-MID LEVEL WARM ADVECTION ALSO
DEVELOPS...WHICH COMBINED WITH OROGRAPHIC ENHANCEMENT LEADS TO
MODERATE TO HEAVY SNOW.  THE HEAVIER SNOW TOTALS ARE EXPECTED IN
THE WA CASCADES...WITH LIGHTER AMOUNTS AS YOU HEAD SOUTH ALONG THE
OR CASCADES.

THE MODELS ARE STARTING TO CONVERGE ON THE AMPLITUDE/TIMING OF THE
TROUGH
WITH EACH SOLUTION PRODUCING SEVERAL INCHES OF SNOW.  AMOUNTS
TAPER AGAIN ON DAY 3 AS THE UPPER TROUGH DEPARTS AND THE APPROACH
OF THE NEXT UPPER RIDGE INDUCES SINKING ALOFT...WITH WARMING
LEADING TO UNFAVORABLE LOWER LAPSE RATES WITH TIME ACROSS THE
NORTHWEST AND THEN NORTHERN ROCKIES.

...NORTHERN MAINE...
THE MODELS SHOW LOW PRESSURE MOVING WEST OF MAINE ACROSS
QUEBEC...PRODUCING A WARM ADVECTION PATTERN ACROSS THE STATE.
INITIAL SOUNDINGS ARE WELL BELOW FREEZING SO A PERIOD OF SNOW IS
LIKELY.  THE SURGE OF WARM AIR DOES RAISE TEMPERATURES ALOFT ABOVE
FREEZING SO A TRANSITION TO MIXED PRECIP TYPES AND RAIN IS
POSSIBLE...OR THE PRECIP COULD END AND MOVE NORTH ACROSS THE
BORDER AS THE WARM FRONT PROGRESSES FURTHER NORTH OUT OF THE
STATE.

...LOWER MICHIGAN...
LIGHT ICING IS EXPECTED IN PARTS OF NORTH CENTRAL TO NORTHERN
LOWER MI ON DAY 1 WITHIN THE MID LEVEL WARM ADVECTION PATTERN AS
TEMPERATURES ALOFT WARM ABV FREEZING ALOFT BEFORE THEY DO AT THE
SFC...RESULTING IN A TRANSITION TO SLEET AND SOME LIGHT FREEZING
RAIN BEFORE ASCENT DEPARTS OUT OF THE AREA.  THE THREAT IS LOW FOR
SIGNIFICANT ACCUMULATIONS DUE TO LIMITED DURATION FOLLOWING
MULTIPLE PRECIP TYPES IN THE AREA.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT DAYS
1...2...AND 3.

PETERSEN


$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.