809
ACUS48 KWNS 210720
SWOD48
SPC AC 210718
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0218 AM CDT TUE JUL 21 2026
VALID 241200Z - 291200Z
..DISCUSSION
..GREAT LAKES/MIDWEST
AN AMPLIFIED UPPER RIDGE WILL PERSIST ACROSS THE PLAINS AND ROCKIES
THROUGH EARLY NEXT WEEK. PERIODS OF STRENGTHENING NORTHWESTERLY
MID/UPPER FLOW ARE EXPECTED ON THE EASTERN PERIPHERY OF THE UPPER
RIDGE AS A SERIES OF UPPER SHORTWAVE TROUGHS MOVE ACROSS THE
CANADIAN PRAIRIES AND GLANCE THE GREAT LAKES VICINITY, MAINLY DAY
5-7/SAT-MON. THIS COULD SUPPORT AREAS OF SEVERE THUNDERSTORM
POTENTIAL ACROSS PARTS OF THE UPPER MIDWEST TO THE OHIO VALLEY
VICINITY DURING THIS TIME AS STRONGER NORTHWESTERLY FLOW OVERSPREADS
A SEASONALLY MOIST AND UNSTABLE AIRMASS. HOWEVER, BOTH TRADITIONAL
PHYSICS-BASED NWP AND ML/AI NWP ARE INCONSISTENT AND/OR SHOW
RELATIVELY LOW/BROAD PROBABILITY AREAS -- INCREASING UNCERTAINTY IN
TIMING AND SPATIAL DELINEATION OF SEVERE POTENTIAL. GIVEN THE
PROXIMITY TO THE UPPER RIDGE, CAPPING MAY BE A CONCERN. TRENDS WILL
BE MONITORED AND SEVERE PROBABILITIES MAY BECOME NECESSARY IS
CONFIDENCE INCREASES IN SUBSEQUENT OUTLOOKS.
..LEITMAN.. 07/21/2026
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