Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 230937
SWOD48
SPC AC 230936

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0336 AM CST Thu Feb 23 2017

Valid 261200Z - 031200Z

...DISCUSSION...
Significant model variability is evident amongst medium-range
deterministic and ensemble data for the Sunday-Thursday (Day 4-8)
period.  Both the GFS/ECMWF and MREF indicate the early stages of a
return-flow pattern from the Gulf of Mexico into the southern Great
Plains on Sunday (Day 4) and show a shortwave trough moving into the
southern High Plains late Sunday.  The UKMET/CMC differ drastically
on the depiction of the mid-level impulse.  On Monday (Day 5), the
recent GFS and MREF model solutions differ substantially from the
ECMWF in the placement of low-level boundaries across the
south-central states and MS Valley.  The deterministic models and
their ensembles generally show the eastward progression of a
larger-scale mid-level trough from the western U.S. on Monday to the
central-southern Rockies on Tuesday.  However, large differences are
noted in relevant low-level mass fields --effectively resulting in
large uncertainty and a predictability-too-low highlight for the
entire Day 4-8 period.

..Smith.. 02/23/2017



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