605
ACUS02 KWNS 061717
SWODY2
SPC AC 061716
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1216 PM CDT SUN SEP 06 2026
VALID 071200Z - 081200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTH-CENTRAL UNITED STATES...
..SUMMARY
STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS PORTIONS OF THE
NORTHERN AND CENTRAL PLAINS INTO MINNESOTA ON MONDAY.
.. SYNOPSIS
A MID-LEVEL SHORTWAVE TROUGH WILL TAKE ON INCREASINGLY NEGATIVE TILT
ON MONDAY AS IT LIFTS NORTH-NORTHEAST ALONG THE NORTHWEST PERIPHERY
OF A CENTRAL CONUS RIDGE. AT THE SAME TIME, A SUBTLE, LOW-AMPLITUDE
SHORT-WAVE TROUGH CURRENTLY OVER THE PACIFIC OCEAN OFF THE COAST OF
SOUTHERN CALIFORNIA WILL QUICKLY MOVE NORTHEAST AHEAD OF THE MAIN
WAVE.
AT THE SURFACE, AN ANTICYCLONE OVER THE UPPER GREAT LAKES WILL
MAINTAIN SOUTH-SOUTHEASTERLY FLOW ACROSS THE PLAINS, SUSTAINING
MID-TO-UPPER-60FS DEWPOINTS ACROSS THE MISSOURI VALLEY INTO THE
DAKOTAS AND WESTERN MINNESOTA. A WEAK LOW ACROSS EASTERN MONTANA
WILL EVENTUALLY REDEVELOP NORTHWARD INTO THE CANADIAN PRAIRIES
OVERNIGHT. AS THIS HAPPENS, A COLD FRONT WILL MOVE EAST ACROSS THE
NORTHERN PLAINS.
.. NORTHERN PLAINS INTO THE UPPER MIDWEST
THE LEAD SHORT-WAVE TROUGH WILL BE APPROACHING THE NORTH-CENTRAL US
AT THE START OF THE FORECAST PERIOD (MONDAY MORNING). AS THE
ASSOCIATED MID-LEVEL JET APPROACHES, THE LOW-LEVEL JET WILL INCREASE
AND SPREAD NORTHWARD ACROSS THE PLAINS. ON THE NOSE OF THIS JET,
ELEVATED CONVECTION IS LIKELY TO BE ONGOING IN RESPONSE TO THE
WARM-AIR ADVECTION. LATEST MODEL GUIDANCE MAINTAINS THE LOW-LEVEL
JET THROUGH THE DAY AND SUBSEQUENTLY THE MORNING CONVECTION IS
LIKELY TO PERSIST THROUGH THE DAY AS IT MOVES NORTHEAST TOWARD
WESTERN MINNESOTA. ALTHOUGH WIDESPREAD CLOUD COVER AND MOIST
MID-LEVEL PROFILES WILL LIMIT INSTABILITY, THE DEGREE OF THE
CLOUD-LAYER SHEAR WILL SUPPORT AT LEAST SOME POTENTIAL FOR HAIL WITH
THESE ELEVATED STORMS.
TO THE SOUTHWEST OF THE MORNING CONVECTION, CLEARING CLOUDS WILL
GIVE WAY TO ROBUST HEATING ALLOWING SURFACE TEMPERATURES TO CLIMB
INTO THE UPPER-80FS TO MID-90FS, WITH EVEN HOTTER SURFACE
TEMPERATURES ACROSS WESTERN NEBRASKA. THIS WILL ALLOW STRONG
INSTABILITY TO DEVELOP BY LATE AFTERNOON AHEAD OF THE SURFACE COLD
FRONT/DRY LINE.
ISOLATED TO PERHAPS SCATTERED THUNDERSTORMS ARE POSSIBLE DURING THE
AFTERNOON ALONG THE SURFACE FRONT/DRYLINE. HOWEVER, LOW-LEVEL
CONVERGENCE ALONG THIS BOUNDARY WILL BE SOMEWHAT WEAK, WITH
SOUTHERLY/SOUTHWESTERLY FLOW AHEAD OF IT. AT THE SAME TIME,
LARGE-SCALE SUBSIDENCE WILL LIKELY BE OCCURRING IN THE WAKE OF THE
MORNING CONVECTION. THIS SHOULD LIMIT STORM COVERAGE ACROSS WESTERN
SOUTH DAKOTA AND WESTERN NEBRASKA. NORTHWEST NORTH DAKOTA AND
EASTERN MONTANA WILL BE CLOSER TO THE MAIN WAVE AS ITS ASSOCIATED
BETTER LARGE-SCALE ASCENT. THUS, STORM COVERAGE MAY BE SLIGHTLY
HIGHER HERE DURING THE AFTERNOON. ISOLATED LARGE HAIL AND STRONG
WIND GUSTS WILL BE POSSIBLE WITH ANY OF THESE STORMS.
OVERNIGHT, THE LOW-LEVEL JET INCREASES IN RESPONSE TO THE MAIN WAVE
APPROACHING THE AREA. THIS SHOULD RESULT IN ADDITIONAL ELEVATED
THUNDERSTORM DEVELOPMENT FROM NORTHEAST NEBRASKA INTO THE EASTERN
DAKOTAS. THIS ACTIVITY SHOULD CONTINUE EAST ACROSS MINNESOTA THROUGH
THE OVERNIGHT. OVERALL INSTABILITY SHOULD BE ON THE LOW SIDE GIVEN
THE CONVECTION FROM THE LEAD SHORTWAVE, BUT STRONG CLOUD-LAYER SHEAR
COULD SUPPORT A HAIL AND WIND THREAT WITH THE STRONGEST ELEVATED
CONVECTION.
..MARSH.. 09/06/2026
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