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
   Air Quality
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/
Warnings

Satellite and Radar Imagery
   Satellite Images
   National Radar
Product Archive
WPC Verification
   QPF
   Medium Range
   Model Diagnostics
   Event Reviews
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
 
(Latest Discussion - Issued 0637Z Nov 01, 2014)
 
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
236 AM EDT SAT NOV 01 2014

VALID 12Z TUE NOV 04 2014 - 12Z SAT NOV 08 2014

...OVERVIEW...

FROM THE MULTI-DAY MEAN PERSPECTIVE MOST GUIDANCE IS SHOWING A
RIDGE NEAR OR JUST INLAND FROM THE WEST COAST AND TROUGHING
DOWNSTREAM OVER THE ERN HALF OF THE CONUS.  HOWEVER AS WAS THE
CASE YDAY THERE ARE SOME SIGNIFICANT INTERMEDIATE-SCALE ISSUES
THAT LOWER CONFIDENCE IN FCST SPECIFICS.  SPECIFICALLY THESE ARE
TIMING OF ERN PAC TROUGH ENERGY EXPECTED TO REACH THE WEST COAST
LATE IN THE WEEK AND RESULTING TIMING/AMPLITUDE OF THE ERN
TROUGH... ALONG WITH SRN STREAM FLOW THAT MAY CLOSE OFF AN UPR LOW
OVER NWRN MEXICO OR ELSE BE MORE PROGRESSIVE/SHEARED.


...GUIDANCE EVALUATION/PREFERENCES...

FROM EARLY IN THE PERIOD THERE IS STILL CONSIDERABLE
MODEL/ENSEMBLE SPREAD REGARDING HOW INITIAL SRN ROCKIES/NWRN
MEXICO ENERGY EVOLVES OVER THE COURSE OF THE PERIOD.  VERSUS PRIOR
RUNS... THE PAST TWO RUNS OF THE ECMWF MEAN REFLECT MOST
OPERATIONAL ECMWF/UKMET RUNS THAT HAVE BEEN DEPOSITING A CLOSED
LOW OVER NWRN MEXICO.  GFS AND SOME GEFS MEAN RUNS HAVE TENDED TO
BE RATHER PROGRESSIVE... THOUGH IT IS NOTED THAT THE NEW 00Z RUN
HAS ADJUSTED SLOWER AND 18Z/00Z PARALLEL GFS RUNS LEAN MORE TOWARD
LEAVING BEHIND AT LEAST SOME ENERGY OVER NWRN MEXICO.  THUS WOULD
PREFER TO INCORPORATE SOMEWHAT MORE OF THE SLOWER/CLOSED SCENARIO
FOR THIS ENERGY.

NRN STREAM TIMING ISSUES ORIGINATE OVER THE PACIFIC ALREADY NEAR
THE START OF THE PERIOD WITH RESULTING ERN CONUS DIFFS BECOMING
APPARENT BY DAYS 4-5 WED-THU.  IN GENERAL THE 12Z ECMWF AND TO A
SLIGHTLY LESSER EXTENT ECMWF MEAN ARE ON THE FASTER SIDE OF THE
FULL GUIDANCE SPREAD WITH BOTH THE ERN PAC SHRTWV HEADING INTO THE
MEAN RIDGE AS WELL AS THE AMPLIFYING ERN TROUGH THAT SHOULD
SUPPORT WHAT COULD BE A FAIRLY VIGOROUS SFC SYSTEM AFFECTING THE
NERN STATES BY LATE IN THE WEEK.  REMAINING SOLNS HAVE BEEN QUITE
DIVERSE WITH ERN PAC SHRTWV TIMING IN PARTICULAR.  GIVEN
ESTABLISHED WPC CONTINUITY LATEST PREFS WERE TO EMPHASIZE NEARLY
EVEN WEIGHTING OF THE 12Z ECMWF MEAN AND THE SLIGHTLY SLOWER 18Z
PARALLEL GFS... WITH THE LATTER ALSO INCLUDED TO DEEPEN THE NERN
SYSTEM SOMEWHAT AS RECOMMENDED BY SOME OPERATIONAL MODEL RUNS. 
NOTE THAT THE NEW 00Z GFS/GEFS/UKMET/CMC RUNS DISPLAY MORE
PRONOUNCED CLUSTERING TOWARD SLOWER TIMING THAN THE 12Z
ECMWF/ECMWF MEAN.  THE 00Z ECMWF THROUGH WED HAS ADJUSTED SLOWER
BUT IS STILL A LITTLE FASTER THAN THE GFS CLUSTER. 

BASED ON GUIDANCE THROUGH THE 18Z CYCLE... COMBINED PREFS FOR NRN
AND SRN STREAM FEATURES LED TO THE USE OF A 40/40/20 BLEND OF THE
18Z PARALLEL GFS/12Z ECMWF MEAN/12Z NAEFS MEAN THROUGH DAY 5
THU... TRENDING TOWARD A BLEND OF 12Z ECMWF MEAN/18Z GEFS MEAN/12Z
NAEFS MEAN BY DAY 7 SAT GIVEN REDUCED CONFIDENCE IN ANY
OPERATIONAL MODEL DETAILS.


...SENSIBLE WEATHER HIGHLIGHTS...

LOCATIONS FROM THE RIO GRANDE VLY INTO THE LOWER OH VLY HAVE THE
BEST POTENTIAL FOR AREAS OF HVY RNFL... WITH A WAVY FRONTAL
BOUNDARY INTERACTING WITH LOW LVL GULF INFLOW AND ADDED INPUT OF
MSTR FROM ERN PAC T.S. VANCE.  ONGOING QUESTION MARKS WITH UPR LVL
FLOW INITIALLY OVER THE SRN ROCKIES/NWRN MEXICO LEAD TO LOWER THAN
DESIRED CONFIDENCE ON COVERAGE/DURATION OF HEAVIEST ACTIVITY.  IN
ADDITION BY LATE IN THE PERIOD NRN STREAM INTERACTION COULD DRAW
SOME OF THIS MSTR NWD/NEWD BUT SOLNS ARE QUITE VARIED IN THIS
REGARD.  MEANWHILE THE PAC NW/EXTREME NRN ROCKIES SHOULD SEE ONE
OR MORE EPISODES OF PCPN ENHANCED OVER FAVORED TERRAIN... AND THE
SYSTEM EXPECTED TO AFFECT THE NORTHEAST LATE IN THE WEEK MAY BE
ACCOMPANIED BY ORGANIZED PCPN INCLUDING SOME SNOW ON THE WRN
PERIPHERY ASSUMING SUFFICIENTLY STRONG DEVELOPMENT.  THE OVERALL
PATTERN SHOULD SUPPORT ABOVE NORMAL TEMPS ON MOST DAYS OVER THE
WEST AND INTO PARTS OF THE NRN/CNTRL PLAINS.  OVER THE EAST NEAR
TO SLIGHTLY ABOVE NORMAL READINGS SHOULD TREND BELOW NORMAL BY
FRI-SAT BUT WITH MOST ANOMALIES REMAINING WITHIN 10F OF NORMAL.

RAUSCH