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FXUS02 KWBC 031820

PMDEPD



Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

220 PM EDT Wed Apr 3 2024



Valid 12Z Sat Apr 06 2024 - 12Z Wed Apr 10 2024





...Heavy rain and flash flooding concerns will increase in the 

southern U.S. next week...





...Pattern Overview...



Initially an omega style blocking pattern will be in place over 

the continental U.S. late this week, with a deep upper low over the

Northeast and another deep low over the West, sandwiching a 

central nation upper ridge. This pattern will be slowly progressive

over the weekend as the northeastern upper low exits into the 

Atlantic and the western low lifts northeastwards towards the Upper

Midwest through mid-next week. As the low lifts, it will be 

accompanied by a surface frontal system that could bring a chance 

of showers to parts of the Central U.S. and the Ohio, Tennessee, 

and Lower Mississippi Valleys (this will likely have implications 

for eclipse viewing on Monday). Another upper low will dig down the

West Coast into the Southwest early in the week and move into the 

south- central U.S. by mid-next week. This pattern will likely 

produce excessive rainfall that could lead to flash flooding in the

southern Plains and Lower Mississippi Valley mid-next week. 





...Guidance/Predictability Assessment...



Model guidance remains in reasonably good agreement on the weather

pattern through the medium range period; however, there is still 

an expected amount of spread and uncertainty for this time range. 

The main differences between model solutions surround the complex 

evolution of the frontal system moving across the central U.S. next

week. There are differences in how the models are handling the 

ejection of the upper low towards the Upper Midwest, which will in 

turn affect timing and location of fronts, precipitation, and cloud

cover. 



The WPC forecast was mainly derived from a multi-model blend of 

the 06 UTC GFS and 00 UTC ECMWF/UKMET/CMC for maximum system detail

through this weekend into Monday. For Tuesday and Wednesday, 

ensemble means from the GEFS and EC ensemble were added to the 

blend in increasing amounts to smooth out model differences and 

maintain trends with the amplified upper pattern. 





...Weather/Hazards Highlights... 



The strong low pressure system that will impact the Northeast late

this week will move offshore by this weekend, but light to locally

moderate precipitation may linger over New England and downwind of

the Great Lakes on Saturday. Brisk northwesterly flow on the 

backside of the system will persist across the Northeast on 

Saturday, then decrease on Sunday as the pressure gradient weakens.



Meanwhile, unsettled weather will impact the Pacific Northwest and

northern and central Rockies as a cold front drops south from 

Canada and a low pressure system strengthens over the Plains. Heavy

snow will be possible for parts of the northern Rockies Saturday 

into Sunday, then conditions will improve as the system progresses 

east. Early next week, this system will bring a large swath of 

showers and thunderstorms (with some severe thunderstorms possible)

across the Plains and Mississippi Valley into the Midwest. This 

system will be relatively slow moving, which could result in 

locally heavy rainfall in some areas. Behind the system, high winds

will spread from the Rockies into the Plains, which will combine 

with dropping humidity to produce a critical wildfire risk over 

eastern New Mexico, the western Half of Texas, and the Oklahoma 

panhandle this weekend. 



Upstream, a renewal of mainly light to moderate precipitation is 

possible along the West Coast early next week as a new Pacific 

upper trough/closed low digs down towards the Southwest. The focus 

for precipitation will then shift to the south-central U.S. Tuesday

into Wednesday, and moist Gulf inflow may be re-energized as a low

pressure system sweeps across the southern tier of the nation. 

Heavy rainfall seems likely across the southern Plains, Lower 

Mississippi Valley, and Mid-South, which may lead to flash flooding

concerns. 



Temperatures will be below average this weekend into early next 

week across the western U.S. as upper level troughing dominates the

weather in this region. Temperatures for much of the West should 

rebound to near or slightly above average by Tuesday, except for in

the Southwest where temperatures will remain cooler than average. 

In the Central U.S., temperatures should remain near to slightly 

above average with areas of below average temperatures under cloud 

cover and precipitation. In the East, colder air will move into the

region behind the departing coastal low, which will result in below

normal temperatures this weekend. Morning lows are forecast to be 

near freezing from the Northeast and Great Lakes into the Mid-

Mississippi, Ohio, and Tennessee Valleys, which could affect 

sensitive vegetation. A warming trend should take root in the East 

and Midwest early next week. 





Dolan/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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