(All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 140838
SPC AC 140838
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CDT Mon Oct 14 2024
Valid 171200Z - 221200Z
...DISCUSSION...
There appears much better consensus between the ECENS/ECMWF and
GEFS/GFS concerning the evolution of the mid/upper flow late this
week into early next week. Within larger-scale mid-level troughing
developing inland of the Pacific coast by mid week, one embedded
short wave impulse progressing northeast of the Canadian Rockies at
the outset of the period is forecast to pivot across the Canadian
Prairies into the higher latitudes of interior Canada, accompanied
by the consolidating primary surface cyclone.
It now appears probable that the significant trailing short wave
perturbation will undergo considerable amplification and split off
the main belt of westerlies, while digging inland of the northern
Pacific coast. It appears that this will include the evolution of a
deepening mid-level low near/east of the Sierra Nevada into the
Southwest, where it may linger into next weekend as low-amplitude
ridging shifts inland within the westerlies across the Canadian
Rockies/Prairies and adjacent international border vicinity. As
westerly mean flow then strengthens downstream of digging
large-scale troughing off the Pacific coast late this weekend into
early next week, it appears that the low will transition to an open
wave and accelerate across the Rockies through the central Great
Plains, around the northern periphery of building ridging in the
subtropical latitudes.
Preceding the emergence of the perturbation from the Southwest, the
models continue to indicate that the development of a moistening
southerly return flow off the Gulf of Mexico will be impeded by the
maintenance of surface ridging across much of the eastern U.S.
through northwestern Gulf coast vicinity. While some strong
thunderstorm development might not be entirely out of the question,
particularly Friday with some modest initial moistening near
lingering relatively deep surface troughing across the central high
plains, the risk for severe weather appears generally low through
this period.
..Kerr.. 10/14/2024
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