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
405
FOUS11 KWBC 112143
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
443 PM EST THU FEB 11 2016

VALID 00Z FRI FEB 12 2016 - 00Z MON FEB 15 2016

...GREAT LAKES...

DEEP NW-WNW FLOW...ALONG WITH STEEP LAPSE RATES WILL CONTINUE TO
SUPPORT WIDESPREAD LAKE EFFECT SNOWS DURING DAYS 1 AND 2 (THROUGH
SAT EVENING). ADDITIONAL SHORTWAVE ENERGY WILL ROUND THE TROUGH
BASE AND PIVOT THROUGH THE UPPER GREAT LAKES ON FRI...THEN THROUGH
THE EASTERN LAKES FRI NIGHT AND SAT. BEHIND THIS NEXT SHORTWAVE
AND SURFACE ARCTIC FRONT...ANOTHER REINFORCING SHOT OF ARCTIC AIR
WILL FOLLOW AS THE BOUNDARY LAYER FLOW BACKS TO THE NW-NNW.
WEST-FLOW LAKE ENHANCED SNOW AHEAD OF THE SHORTWAVE WILL THEREFORE
GIVE WAY TO MORE NW-NNW FLOW LES...EVENTUALLY LOSING THE SYNOPTIC
SUPPORT AND MOISTURE ABOVE THE LOWERING LAKE-INDUCED CBL FROM WEST
TO EAST SAT AFTERNOON (UPPER LAKES) AND SAT NIGHT (LOWER LAKES).
HIGHEST PROBABILITIES OF EXCEEDING 4" DURING DAY 1 (00Z FRI - 00Z
SAT) WILL BE ACROSS THE FAVORABLE W TO NW FLOW LAKE EFFECT
SNOWBELTS IN EASTERN UPPER MI AND NORTHWEST-NORTH CENTRAL LOWER
MI...ALONG WITH THE W TO WSW FLOW LAKE EFFECT SNOWBELTS DOWNWIND
OF LAKES ERIE AND ONTARIO. ON DAY 2 (00Z SAT - 00Z SUN)...THE
HIGHER PROBS SHIFT A LITTLE WEST OVER THE UPPER LAKES (WITH THE
ENSUING NW-NNW FLOW)...INTO CENTRAL UPPER MI... FAR NORTHWEST
LOWER MI...AND ACROSS SOUTHWEST LOWER MI. THE HEAVIER LAKE ERIE
BANDS WILL ALSO SHIFT FARTHER SOUTH ON DAY 2 (INTO FAR NORTHEAST
OH AND NORTHWEST PA).


...PACIFIC NORTHWEST/NORTHERN ROCKIES...

PERSISTENT ONSHORE FLOW AHEAD OF AN APPROACHING UPPER TROUGH WILL
FUEL WIDESPREAD PRECIPITATION ACROSS THE PACIFIC NORTHWEST AND
NORTHERN ROCKIES THIS WEEKEND. ANOMALOUSLY WARM CONDITIONS WILL
INITIALLY KEEP ANY SNOW CONFINED TO THE HIGHEST PEAKS...BUT AS
SHORTWAVE ENERGY EMBEDDED WITHIN THE BASE OF THE TROUGH SPREADS
INLAND LATE FRI NIGHT INTO SAT...THE HIGH-AMPLITUDE RIDGE
CURRENTLY IN PLACE BECOMES SUPPRESSED AND SNOW LEVELS LOWER TO
AROUND 3000 FT ACROSS THE OLYMPICS AND CASCADE RANGES IN WA.
PROBABILITIES OF EXCEEDING 8" IN 24 HOURS CLIMBS TO 40+ PERCENT
OVER THE HIGHEST ELEVATIONS OF THE NORTHERN WA CASCADES ON DAYS 2
AND 3...WHILE ALSO WORKING INTO THE
NORTHERN BITTERROOTS IN IDAHO BY DAY 3 (00Z SUN - 00Z MON).


...NORTHERN PLAINS INTO THE UPPER AND MID MISSISSIPPI VALLEY...

THE AFOREMENTIONED UPPER SHORTWAVE DROPS INTO THE NORTHERN-CENTRAL
HIGH PLAINS LATE SAT...THEN CONTINUE ESE INTO THE MID-UPPER MS
VALLEY ON SUN. LOW LEVEL WAA AND MOISTURE ADVECTION AHEAD OF THIS
SHORTWAVE AND ON THE BACKSIDE OF THE ARCTIC HIGH...ALONG WITH THE
TIGHTENING UPPER LEVEL CONFLUENCE/LOW-MID LEVEL
FRONTOGENESIS...SHOULD SUPPORT A SWATH OF LIGHT-MODERATE SNOWS
ACROSS CENTRAL AND EASTERN PORTIONS OF THE DAKOTAS INTO
WESTERN-SOUTHERN MN...IA...WESTERN IL... AND EAST-NORTHEAST MO.
EASTERN MONTANA INTO THE DAKOTAS ON SATURDAY. HIGHEST
PROBABILITIES OF 4+ INCHES ON DAY 3 (SAT NIGHT-SUNDAY) WILL BE
ACROSS EASTERN SD TO SOUTHWEST MN AND INTO NORTH-CENTRAL-NORTHEAST
IA.


...EASTERN NORTH CAROLINA AND SOUTHEAST VIRGINIA...

WEAK MID-LEVEL ENERGY ROUNDING THE BASE OF A BROAD TROUGH IN THE
EAST WILL HAVE THE POTENTIAL TO PRODUCE A QUICK BURST OF SNOW AND
WINTRY MIX ON FRIDAY AS THE SHORTWAVE AND EVENTUAL SURFACE LOW
STREAKS OFFSHORE FRIDAY EVENING.  LATEST THERMAL PROFILES WOULD
SUPPORT AN AXIS OF SNOW/SLEET...AND MAYBE EVEN FREEZING
RAIN...ACROSS EASTERN NORTH CAROLINA. LESS MODEL SPREAD IS NOTED
IN TERMS OF THE THE QPF AND THERMAL DETAILS...AS THE SYSTEM NOW
MOVES INTO THE SHORT RANGE (DAY 1). WPC UTILIZED A NON
NAM/NON-SREF BLEND WITH THE QPF...GIVEN THAT THESE RUNS REMAINED
ON THE WETTER SIDE OF THE GUIDANCE SPREAD (THOUGH IT SHOULD BE
NOTED THAT THE 18Z NAM HAS TRENDED DRIER ON THE NORTHERN EDGE OF
THE PCPN SHIELD...I.E. ALONG THE VA/NC BORDER AND NORTH).


...MAINE...

AN INVERTED SURFACE TROUGH EXTENDING BACK FROM A LOW LIFTING INTO
THE CANADIAN MARITIMES IS EXPECTED TO FOCUS AN AREA OF MODERATE TO
HEAVY SNOW ACROSS PORTIONS OF MAINE ON SATURDAY INTO SATURDAY
NIGHT. THE WPC FORECAST STARTED WITH A NON-NAM COMPROMISE...WHICH
ESSENTIALLY SPLITS BETWEEN THE UKMET AND ECMWF (FARTHER SOUTH WITH
THE INVERTED TROUGH AND MAX PCPN AXIS) AND THE GFS AND PARALLEL
GFS (FARTHER NORTH).


THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

HURLEY

$$





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