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.
 
Extended Forecast Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0658Z Oct 17, 2018)
 
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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
258 AM EDT Wed Oct 17 2018

Valid 12Z Sat Oct 20 2018 - 12Z Wed Oct 24 2018

...Pattern Overview...

Troughing in the Great Lakes this weekend will be reloaded next
Tue/Wed while the western ridge slowly/stubbornly relents.
Subtropical ridging over Florida will squash into Cuba as a weak
upper low over California drifts through the Great Basin. The
pattern is rather cool/dry for much of the lower 48 besides Texas
and Florida in the vicinity of a stalled front through the Gulf of
Mexico


...Guidance/Predictability Assessment...

Models and ensembles continue to offer good clustering through the
next 5-6 days with expected timing/amplitude differences by next
Tue/Wed. A deterministic blend of the GFS/ECMWF/Canadian/UKMET
offered a good starting point close to continuity for Sat-Mon as a
lead and secondary cold front push off the East coast and another
Canadian front dips into the western Great Lakes. By next Tue/Wed
an approaching Pacific system (or couple of systems) will
eventually break the ridge over the west, but the ECMWF ensembles
remain quickest to lower heights into the Pac NW which is rather
uncharacteristic in the longer term, but has been noted recently.
Preferred to stick closer to the slower cluster of solutions
around the 18Z GEFS mean that included the 12Z GFS/ECMWF.


...Weather Highlights/Threats...

The Pacific Northwest will see several days of above average
temperatures and dry conditions through the weekend. Rain chances
will increase next week starting late Monday as the first cold
front approaches the coast. Warm antecedent temperatures will
preclude snow from all but the highest elevations, but that will
change as cooler air works its way eastward. Rain will become
widespread and moderate to locally heavy by midweek next week. The
rest of the CONUS will see near to below average temperatures with
the core of the coolest air from Texas northeastward to the
Northeast/New England. Even Florida will slowly trend back toward
more typical late October temperatures in the upper 70s (north) to
mid 80s (south).

Coastal Texas has the highest probability of the greatest amount
of precipitation east of the Rockies due to an initial and then
subsequent stationary boundary through the Gulf next to an
inverted trough. Though most of this may stay offshore, areas near
Brownsville may see several inches of rain over the period. Much
less precipitation is expected elsewhere with each frontal passage
except for perhaps Florida with strong easterly flow.
Coastal WA/OR will see light-moderate rain develop and expand
inland early next week as upper troughing approaches with several
inches possible along the immediate coast by next Wednesday.


Fracasso


WPC medium range 500 mb heights, surface systems, weather grids,
quantitative precipitation, winter weather outlook probabilities
and heat indexes are found at:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml