(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.
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 250815
SPC AC 250815
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0315 AM CDT Sat Mar 25 2017
Valid 281200Z - 021200Z
A shortwave trough currently near the International Date Line in the
central Pacific will move eastward and is forecast to deepen over
the western United States on Tuesday. Low-level cyclogenesis over
NM and west TX will help transport Gulf moisture northwestward into
west TX, where steep lapse rates and moderate CAPE values are
expected to develop. Present indications are that scattered strong
to severe thunderstorms (including supercells) will affect parts of
west TX and southwest OK on Tuesday. These storms will move
eastward into north-central TX during the evening/night.
...Day5/Wed Arklatex Region...
00z models show reasonably good agreement that a surface low and
associated low level jet will affect the Arklatex region on
Wednesday. Considerable moisture and instability should reside in
the warm sector of the low, with forecast soundings suggesting a
favorable environment for a few severe thunderstorms from northeast
TX and southeast OK into much of AR and northwest LA.
...Day6/Thu Lower MS Valley...
Beginning on Thursday, model solutions begin to diverge regarding
the strength/timing of pertinent features. The 00z ECMWF/UKMET
solutions would support a risk of severe storms over parts of the
lower MS and TN Valleys. However, the GFS and GEM output indicate
significant uncertainty of this scenario. Therefore will not
include a 15% severe risk area for Thursday at this time.
...Day7/Fri and Day8/Sat...
The next in a series of shortwave troughs will move into the western
states and deepen on Fri/Sat. This system is currently off the
coast of Japan, and models differ substantially regarding the
evolution of the trough. Therefore, confidence in details is low at
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