Skip Navigation Links weather.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
The Weather Prediction Center

 
 

 

Follow the Weather Prediction Center on Facebook Follow the Weather Prediction Center on Twitter
NCEP Quarterly Newsletter
WPC Home
Analyses and Forecasts
   National High & Low
   WPC Discussions
   Surface Analysis
   Days ½-2½ CONUS
   Days 3-7 CONUS
   Days 4-8 Alaska
   QPF
   PQPF
   Flood Outlook
   Winter Weather
   Storm Summaries
   Heat Index
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/
Warnings

Satellite and Radar Imagery
  GOES-East Satellite
  GOES-West Satellite
  National Radar
Product Archive
WPC Verification
   QPF
   Medium Range
   Model Diagnostics
   Event Reviews
   Winter Weather
International Desks
Development and Training
   Development
WPC Overview
   About the WPC
   Staff
   WPC History
   Accomplishments
   Other Sites
   FAQs
Meteorological Calculators
Contact Us
   About Our Site
 
USA.gov is the U.S. Government's official web portal to all federal, state, and local government web resources and services.
 
Winter Weather Forecast Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0937Z Jan 18, 2019)
 
Version Selection
Versions back from latest:  0   1   2   3   4   5   6   7   8   9   10   
 
Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
437 AM EST Fri Jan 18 2019

Valid 12Z Fri Jan 18 2019 - 12Z Mon Jan 21 2019


...South Dakota to the upper and mid Mississippi valley...

Models continue to show a stripe of light to moderate snows
developing along the track of a 700mb wave, axis of low to mid
level frontogenesis and upper divergence shifting east  from South
Dakota into the Mississippi valley on Friday.  Overnight models
remained consistent with previous runs with respect to the axis of
heavier amounts, however the overall consensus was toward a faster
solution.  Meanwhile to the south, models continue to show a
developing deformation zone to the northwest of a deepening
surface cyclone moving east of the Rockies across Oklahoma and
into Arkansas Friday night.  Rain changing to snow is expected to
result in some light to moderate snow accumulations across
portions of the mid Mississippi valley by Saturday morning.

...Ohio Valley to the northern Mid Atlantic and Northeast...

Models show the previously noted surface wave and associated
deformation band continuing to produce light to moderate snows as
they track further to the northeast along the Ohio valley on
Saturday.  As the low moves toward the Mid-Atlantic, phasing mid
level energy is expected to support significant surface
intensification, with the models continue to show a strong signal
for heavy snows developing north of the low track.  Strong upper
divergence within a coupled jet region, along with low-mid level
frontogenesis continues to support a strong signal for heavy
amounts extending from the upper Ohio valley to northern New
England.  WPC Day 2 probabilities (ending 12Z Sun) show a High
Risk (greater than 70 percent chance) for amounts exceeding
8-inches from northeast Ohio to southern New Hampshire, with WPC
probabilities also indicating the strong likelihood that some
areas within this region will see amounts of a foot or more.  An
icy transition zone is expected further to the south, with
guidance continuing to signal some potential for significant ice
accumulations along the southern periphery of the heavier snow
axis from the Ohio valley to southern New England on Day 2.  With
the low deepening rapidly along the northern New England coast,
heavy snows will continue to shift north across northern New
England, with WPC Day 3 probabilities (ending 12Z Mon) showing a
High Risk for additional accumulations of 8-inches or more
centered across eastern Maine.

...California, Pacific Northwest, Great Basin, Central to Northern
Rockies...

Warm advection precipitation ahead of a wave tracking northeast
across the eastern Pacific toward British Columbia is expected to
produce some locally heavy accumulations across portions of the
northern Cascades and northeast Oregon ranges Friday into early
Saturday.  Locally heavy amounts are expected to extend further to
the east into the central Idaho and western Wyoming ranges along a
low to mid level frontal band dropping southeast across the region
Saturday into early Sunday.  By late Sunday as the upper ridge
begins to give way to a well-defined shortwave trough, the
potential for heavy snows will become more widespread, with
locally heavy snows becoming more likely from the Cascades and
northern Sierra to the northern Rockies.

Pereira