Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1132 AM EDT Fri Nov 01 2019
Valid 12Z Mon Nov 04 2019 - 12Z Fri Nov 08 2019
1530 UTC Update...
Overall, the large scale pattern across the CONUS shows above
average predictability during the medium range. A building ridge
from the northeastern Pacific north across Alaska toward the
Arctic will favor a persistent and broad upper trough across the
north central/northeastern U.S. Changes to the ongoing forecast
were minor, and the forecast was updated to reflect a blend of the
latest deterministic guidance (00Z ECMWF/UKMET/06Z GFS), with more
weight toward the ECENS/GEFS ensemble means by late next week. The
previous discussion follows below.
Ryan
Previous Discussion (issued at 0621 UTC)...
...Pattern Overview/Weather Threats and Guidance Assessment...
Broad cyclonic flow aloft will dominate much of the lower 48 next
week as a series of impulses reinforce a central North American
mean upper longwave trough. This trough may gradually shift
eastward as east Pacific upper ridging grudgingly work into a dry
West Coast. The pattern will favor the spread and periodic
reinforcement with colder than normal airmasses from the Rockies
and Central U.S. to the East as post-frontal high pressure cells
spill down from Canada. Moisture will be mainly limited across the
mid-higher latitudes, but the passage of several clipper lows
should support modest snow/rain swaths over the U.S. northern tier
from the Rockies through the Great Lakes/Northeast where activity
will be prolonged by lake effect. Moisture may sufficiently feed
into/over a wavy lead front to fuel some moderate rains for FL and
the coastal Southeast/Carolinas early next week, then back over
the southern Plains mid-later next week where cooled temperatures
offer some risk of a light icy coating on the far northern
periphery of return flow with secondary frontal passages.
The WPC medium range product suite was primarily derived from a
composite blend of the quite compatable latest GEFS/ECMWF ensemble
means in lue of reliance on deterministic models that show more
run to run continuity issues with the timings/amplitudes of
embedded weather systems.
Schichtel
Additional 3-7 Day Hazards information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation, winter weather outlook probabilities
and heat indices are 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