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FXUS02 KWNH 080701
PREEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
200 AM EST Wed Jan 8 2025

Valid 12Z Sat Jan 11 2025 - 12Z Wed Jan 15 2025

...Guidance/Predictability Assessment...

It remains the case that model and ensemble forecast spread
continues to decrease, with higher agreement and run-to-run
consistency. There is a bit more model spread concerning weaker
features early-mid next week, but the affect on sensible weather
should be minimal since no strong storm systems are anticipated.

Accordingly. the WPC medium range product suite was mainly derived
from a blend of reasonably well clustered guidance of the
GFS/ECMWF/Canadian/UKMET along with the National Blend of Models.
Later in the period, added GEFS/ECMWF/Canadian ensemble means input
to additionally smooth out differences in the deterministic
models. This plan maintains good WPC continuity and is in line with
a composite of latest 00 UTC cycle guidance.

...Weather/Hazards Highlights...

A developing low pressure system moving up from the Gulf of Mexico
over the next few days will interact with an arctic air mass
across the central and eastern U.S. to bring heavy snow, sleet, and
rain/freezing rain. Lingering wintry weather Saturday may bring
some hazardous conditions out from the South to the Mid-Atlantic
and coastal New England as the low lifts offshore Sunday to rapidly
deepen over the Western Atlantic as a maritime threat. Trailing
fronts will continue to focus periodic rain/convection back across
Florida and the Gulf to southern Texas into early-mid next week.

Wintry weather is also expected out from the Northwest by Saturday
as
a frontal system tracks increasingly inland. This system will push
across the Rockies and Plains/Midwest/Great Lakes this weekend
into early
next week and weaken while high pressure ridging builds over the
West. By Sunday, another blast of Arctic air is forecast to spill
into the northern Plains and Upper Midwest as a cold front drops
south over the central U.S., creating hazardous cold temperatures.

This weather pattern will favor the continuation of well below
normal temperatures for much of the nation. The exiting winter
storm over the South will bring temperature anomalies of 10-20
degrees below normal. Temperatures will moderate slightly this
weekend, but remain below normal, then another arctic blast is set
to move into the northern Plains and Upper Midwest early next week.
This surge of Arctic air will drop temperatures 10-15 degrees
below normal, with single digit/teen highs and lows below zero.

Schichtel


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

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/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw





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