682
ACUS48 KWNS 280851
SWOD48
SPC AC 280849
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0349 AM CDT FRI AUG 28 2026
VALID 311200Z - 051200Z
..DISCUSSION
AN UPPER RIDGE WILL MEANDER EASTWARD ACROSS THE CENTRAL AND EASTERN
CONUS THROUGH THE WEEK, WITH MULTIPLE MID-LEVEL SHORTWAVE TROUGHS
AND OTHER SMALLER EMBEDDED IMPULSES POISED TO PIVOT AROUND THE RIDGE
AND TRAVERSE THE NORTHERN PLAINS TO THE MID-ATLANTIC. SEVERAL DAYS
OF AT LEAST SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED
ALONG THE PERIPHERY OF THE UPPER RIDGE AS APPRECIABLY STRONG
MID-LEVEL FLOW OVERSPREADS A SEASONABLY MOIST BOUNDARY LAYER,
ESPECIALLY DURING THE MIDDLE OF THE WEEK. BY THE END OF THE WEEK,
APPRECIABLE INSTABILITY BUILDS BACK INTO THE NORTHERN PLAINS AND
UPPER MS VALLEY, BUT PREDICTABILITY IS TOO LOW TO ASCERTAIN ANY
LOCALIZED SEVERE POTENTIAL THIS FAR IN ADVANCE.
..OH VALLEY TO THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND
THE STRONGEST SIGNAL FOR SEVERE THUNDERSTORMS CURRENTLY EXISTS FOR
DAYS 5-6 (TUESDAY-WEDNESDAY). GUIDANCE DIFFERS ON THE DETAILS
REGARDING PLACEMENT AND TIMING OF MID-LEVEL TROUGHS/IMPULSES ON DAY
5 (TUESDAY), THOUGH SEVERE THUNDERSTORMS WILL PROBABLY DEVELOP
SOMEWHERE BETWEEN THE EASTERN GREAT LAKES TO THE EASTERN SEABOARD.
ONCE DETAILS BECOME CLEARER ON WHERE STORM DEVELOPMENT IS MOST
LIKELY, 15 PERCENT SEVERE PROBABILITIES WILL LIKELY BE INTRODUCED.
FOR DAY 6 (WEDNESDAY), THERE IS A GENERAL CONSENSUS AMONG
MEDIUM-RANGE GUIDANCE THAT AT LEAST ONE IMPULSE WILL TRAVERSE THE
EASTERN GREAT LAKES TO THE MID-ATLANTIC/SOUTHERN NEW ENGLAND
CORRIDOR. A 50+ KT MID-LEVEL NORTHWESTERLY 500 MB JET WILL
OVERSPREAD MID 60S F SURFACE DEWPOINTS, YIELDING BOTH 1500+ J/KG
MLCAPE AND 40-50 KTS OF EFFECTIVE BULK SHEAR AMID A CONVECTIVE
SIGNAL. AS SUCH, A 15 PERCENT SEVERE AREA HAS BEEN INTRODUCED FOR
WEDNESDAY WHERE THESE AFOREMENTIONED INGREDIENTS BEST OVERLAP.
..SQUITIERI.. 08/28/2026
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