842
ACUS02 KWNS 040512
SWODY2
SPC AC 040510
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1210 AM CDT SAT JUL 04 2026
VALID 051200Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SUNDAY
AFTERNOON AND EVENING ACROSS PARTS OF THE MID ATLANTIC...
..SUMMARY
DEVELOPING THUNDERSTORM CLUSTERS MAY POSE A RISK FOR DAMAGING WIND
GUSTS ACROSS PARTS OF THE MID ATLANTIC AND PARTS OF THE SOUTHERN
GREAT PLAINS SUNDAY AFTERNOON AND EVENING.
..DISCUSSION
WHILE RIDGING IN THE SUBTROPICAL LATITUDES REMAINS RELATIVELY
SUPPRESSED, MODELS INDICATE THAT THE STRONGER MID-LATITUDE
WESTERLIES WILL REMAIN CONFINED TO THE NORTHERN MID-LATITUDES
THROUGH THIS PERIOD. WITHIN THIS REGIME, A MID-LEVEL SHORT WAVE
TROUGH IS FORECAST TO ACCELERATE EAST OF THE CANADIAN MARITIMES AND
NEW ENGLAND EARLY SUNDAY, BEFORE MERGING INTO A SIGNIFICANT TROUGH
AND EMBEDDED MID-LEVEL LOW DIGGING ACROSS/SOUTHEAST OF THE LABRADOR
SEA.
UPSTREAM, MID-LEVEL TROUGHING, INCLUDING AT LEAST A COUPLE OF
EMBEDDED SMALLER-SCALE PERTURBATIONS, IS FORECAST TO CONTINUE
PROGRESSING ACROSS AND EAST-NORTHEAST OF THE CANADIAN PRAIRIES. IT
APPEARS THAT FORCING WITH THE LEAD IMPULSE MAY SUPPORT MODEST
SURFACE CYCLOGENESIS ACROSS NORTHERN SASKATCHEWAN THROUGH MANITOBA.
HOWEVER, EVEN WITH THE TRAILING PERTURBATION, IT APPEARS THAT
FORCING FOR ASCENT WILL GENERALLY REMAIN FOCUSED TO THE NORTH OF THE
INTERNATIONAL BORDER.
TO THE SOUTH OF THE INTERNATIONAL BORDER, MODELS SUGGEST THAT
MID-LEVEL RIDGING, ACROSS THE EASTERN GREAT BASIN INTO NORTH CENTRAL
GREAT PLAINS AT THE OUTSET OF THE PERIOD, WILL EXPAND ACROSS THE
MIDDLE MISSOURI VALLEY TOWARD UPPER MISSISSIPPI VALLEY SUNDAY
THROUGH SUNDAY NIGHT. DOWNSTREAM, IT APPEARS THAT WEAK TROUGHING,
LIKELY WITH A NUMBER OF EMBEDDED CONVECTIVELY GENERATED
PERTURBATIONS, WILL CONTINUE TO OVERSPREAD THE MIDDLE MISSISSIPPI
AND OHIO VALLEYS THROUGH NORTHERN MID ATLANTIC.
TO THE EAST AND SOUTH OF THIS TROUGHING, SEASONABLY HIGH
BOUNDARY-LAYER MOISTURE CONTENT MAY AGAIN BECOME SUPPORTIVE OF
MODERATE TO STRONG POTENTIAL INSTABILITY. HOWEVER, GIVEN THE
GENERALLY WEAK NATURE OF THE LARGE-SCALE FLOW AND SYNOPTIC FORCING,
SEVERE THUNDERSTORM POTENTIAL WILL LARGELY BE INFLUENCED BY
SUB-SYNOPTIC DEVELOPMENTS WITH RATHER LOW PREDICTABILITY AT THIS
EXTENDED TIME FRAME. THIS CONTINUES TO BE REFLECTED IN SIZABLE
SPREAD EVIDENT IN CONVECTION ALLOWING AND RELATED GUIDANCE.
..MID ATLANTIC
THERE REMAINS LITTLE GENERAL CHANGE FROM PRIOR MODEL OUTPUT. IT
STILL APPEARS THAT A LOW-LEVEL BAROCLINIC ZONE COULD REMAIN FAIRLY
WELL DEFINED TO THE NORTH AND NORTHEAST OF A SURFACE LOW FORECAST TO
DEVELOP TO THE LEE OF THE BLUE RIDGE BY LATE SUNDAY AFTERNOON. BOTH
OF THESE FEATURES COULD BECOME A FOCUS FOR VIGOROUS THUNDERSTORM
DEVELOPMENT, THOUGH THERE APPEARS A BETTER SIGNAL IN LATEST GUIDANCE
FOR ACTIVITY TO FORM OFF THE HIGHER TERRAIN INTO THE LEE SURFACE
TROUGH, AT LEAST INITIALLY, BEFORE PERHAPS PROPAGATING ALONG OR JUST
SOUTH OF THE REMNANT FRONT TOWARD COASTAL AREAS. AIDED BY A
LINGERING MODEST, BUT WEAKENING, BELT OF CONVECTIVELY AUGMENTED
WESTERLY FLOW, IT IS POSSIBLE THAT ONE OR TWO CLUSTERS COULD
ORGANIZE AND BECOME ACCOMPANIED BY BETTER POTENTIAL TO PRODUCE
DAMAGING WIND GUSTS LATE SUNDAY AFTERNOON AND EVENING.
..SOUTHERN ROCKIES INTO ADJACENT GREAT PLAINS
UNCERTAINTY APPEARS EVEN GREATER THAN SUGGESTED IN PRIOR MODEL RUNS,
PARTICULARLY WITH REGARD TO WHETHER THERE WILL BECOME A WELL-DEFINED
BOUNDARY, SUPPORTED BY DIFFERENTIAL SURFACE HEATING BY LATE
AFTERNOON, TO FOCUS STRONG THUNDERSTORM DEVELOPMENT. THE HIGHER
TERRAIN OF THE SOUTHERN SANGRE DE CRISTO MOUNTAINS INTO THE RATON
MESA/RIDGE VICINITY APPEARS TO OFFER THE MOST PROBABLE FOCUS FOR
THUNDERSTORM DEVELOPMENT BY LATE SUNDAY AFTERNOON. THERE IS SOME
SIGNAL THAT ACTIVITY COULD CONSOLIDATE INTO A CLUSTER WHILE
PROPAGATING SOUTHEAST OF THE HIGHER TERRAIN INTO A RESIDUAL DEEPLY
MIXED BOUNDARY LAYER OVER THE HIGH PLAINS SUNDAY EVENING,
ACCOMPANIED BY POTENTIAL TO PRODUCE STRONG WIND GUSTS.
..NORTHWESTERN NORTH DAKOTA
THERE REMAINS A MIXED SIGNAL WITHIN MODEL OUTPUT CONCERNING
POTENTIAL DESTABILIZATION AND THUNDERSTORM DEVELOPMENT ALONG SURFACE
TROUGHING EXTENDING SOUTH OF THE INTERNATIONAL BORDER LATE SUNDAY
AFTERNOON AND EVENING. WITH STRONGER MID/UPPER SUPPORT LIKELY TO
REMAIN TO THE NORTH OF THE BORDER, THE POTENTIAL SEEMS LOW, BUT LOW
SEVERE PROBABILITIES WILL BE MAINTAINED, AT LEAST FOR NOW.
..KERR.. 07/04/2026
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