286
FXUS02 KWNH 080659
PREEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
158 AM EST Fri Nov 8 2024

Valid 12Z Mon Nov 11 2024 - 12Z Fri Nov 15 2024

...Hurricane Rafael not likely a threat to the Gulf Coast...

...Overview...

The National Hurricane Center continues to issue advisories for
Hurricane Rafael in the Gulf of Mexico, but based on the current
official forecast track, Rafael should be weakening and moving
southward into the Bay of Campeche by Monday and therefore likely
not a threat to the U.S. Gulf Coast aside from some tropical
moisture across the Southeast. Farther west, a large scale system
will bring an episode of rain and high elevation snow to the
Pacific Northwest through the Rockies into Monday with this system
continuing into the eastern half of the country by mid- late week.
Another system should focus additional precipitation over the
Northwest by midweek. Expect above normal temperatures over most of
the East through about Wednesday while the upper trough crossing
the West early next week will bring a couple days of cooler
temperatures to the region.


...Guidance/Predictability Assessment...

Continue to monitor latest NHC products for additional information
on Hurricane Rafael which should weaken by the start of the medium
range period as it tracks over the Gulf of Mexico. There remains
some uncertainty late weekend/early next week on the exact track as
some ensemble members (and still the CMC) bring the center near or
over the central Gulf Coast (in a very weakened state), but these
solutions are considered outliers. The most recent NHC forecast
track continues to show a preference more like the ECMWF/UKMET with
a southwestern dive toward the Bay of Campeche and possibly into
Mexico as a weak surface low. Despite the spread, at least it is
pretty clear that the center of Rafael itself should not impact the
U.S., aside from some tropical moisture spreading northward into
the Southeast.

A weak shortwave into the Midwest on Monday already shows some
uncertainty in strength. The CMC tries to close off a low over the
Southeast by Tuesday and is an outlier in doing so. Prefer a weaker
shortwave that moves through the Northeast as suggested by
ensemble mean guidance. Behind this, the next system moves into the
West by Monday with quite a bit of uncertainty Tuesday and beyond
as it moves East. The ECMWF continues to be slower and a little
deeper with this system, while the better consensus (and WPC
continuity) is more progressive into the Midwest/Northeast
Wednesday and beyond. Prefer a blend towards the GFS, CMC, and
ensemble means for this system. Another shortwave enters the
Northwest later in the week and WPC prefers a non-GFS blend for
this system since the GFS is significantly slower.


...Weather/Hazards Highlights...

Some tropical moisture from Rafael may extend northward and focus
along a frontal boundary through the Southeast early in the week,
but outside of very localized heavy rainfall pockets, limited
instability is expected to limit the overall threat.

An upper trough with leading surface front focusing an atmospheric
river will approach the Pacific Northwest and then move inland by
Monday, bringing an episode of focused precipitation to the region.
Given anticipated rainfall beginning on Sunday at the end of the
short range period, a marginal risk remains in place for the new
Day 4/Monday Excessive Rainfall Outlook covering the Pacific
Northwest into northern California. Another AR looks to take aim
into the Pacific Northwest by later in the Day 5/Tuesday period,
and so a marginal risk is also depicted on the ERO that day as
well. Precipitation from this system should extend into Wednesday
and Thursday as well. Modest snowfall is expected in the higher
elevations of the Cascades and into the northern Rockies with these
systems.

The system affecting the West early in the week will progress
eastward and bring some areas of precipitation to the eastern half
of the country during at least parts of the Tuesday-Thursday
period. Important lower-predictability details still have to be
resolved before confidence can increase regarding specifics of
where/when the greatest totals will occur. But the low track near
the Great Lakes could spread moderate to high winds especially over
the waters but possibly for some land areas like Michigan`s Upper
Peninsula.

While system progression will provide some day-to-day variability,
much of the eastern half of the country should see well above
normal temperatures into mid-week. Expect the warmest anomalies to
be for morning lows, with morning temps 15-20F above normal over
the Southeast/Mid-Atlantic early Monday. Broadest coverage of plus
10F or greater highs should be during Monday- Wednesday. The
northern and southern thirds of the Plains will also see a period
of warmth Monday-Tuesday (and still southern Texas on Wednesday).
Corresponding to these relative anomalies, there will be better
potential for some record warm lows versus more isolated records
for daytime highs. Parts of the Northeast may be near normal at
times though with more seasonable normal temperatures returning to
much of the East late in the week. The southern Rockies/High Plains
will remain chilly to the extent that snow cover lingers, while
the upper trough crossing the West early next week will bring a
brief period of moderately below normal temperatures.


Santorelli


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.phpSchichtel/Hamrick

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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