255
ACUS02 KWNS 090520
SWODY2
SPC AC 090518
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1218 AM CDT FRI MAY 09 2025
VALID 101200Z - 111200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SATURDAY ACROSS
PARTS OF CNTRL AND NORTHERN FL...SRN GA...AND WRN INTO CNTRL MT...
..SUMMARY
STRONG THUNDERSTORMS MAY IMPACT PARTS OF NORTHERN AND CENTRAL
FLORIDA AND ADJACENT SOUTHERN GEORGIA ON SATURDAY. ADDITIONAL
STRONG THUNDERSTORMS MAY IMPACT PARTS OF WESTERN INTO CENTRAL
MONTANA. SOME OF THESE STORMS MAY BE ACCOMPANIED BY AT LEAST SOME
RISK FOR SEVERE WEATHER.
..DISCUSSION
IT APPEARS THAT MUCH OF NORTH AMERICA WILL REMAIN UNDER THE
INFLUENCE OF SPLIT, AMPLIFIED WESTERLIES THROUGH THIS PERIOD AND
BEYOND, WITH FLOW IN THE NORTHERN MID-LATITUDES REMAINING STRONGER
THAN IN THE SOUTHERN MID- AND SUBTROPICAL LATITUDES. WITHIN THIS
REGIME, A SIGNIFICANT MID-LEVEL TROUGH IS FORECAST TO CONTINUE
DIGGING OFFSHORE OF THE BRITISH COLUMBIA COAST TOWARD THE PACIFIC
NORTHWEST, PRECEDED INLAND BY A LESS PROMINENT, NORTHEASTWARD
ACCELERATING PERTURBATION INTO/ACROSS AND EAST-NORTHEAST OF THE
CANADIAN ROCKIES.
MODELS INDICATE THAT THE LEAD PERTURBATION MAY BE ACCOMPANIED BY
WEAK CYCLOGENESIS TO THE LEE OF THE CANADIAN AND ADJACENT NORTHERN
U.S. ROCKIES, AS IT BEGINS TO PROGRESS AROUND THE WESTERN PERIPHERY
OF LARGE-SCALE MID-LEVEL RIDGING SHIFTING ACROSS/EAST OF THE
CANADIAN PRAIRIES, NORTHERN U.S. GREAT PLAINS AND UPPER MIDWEST.
AS THE RIDGING OVERSPREADS THE INTERIOR NORTHERN TIER OF THE U.S.,
IT APPEARS THAT A BROAD MID-LEVEL LOW, INITIALLY CENTERED JUST
INLAND OF THE NORTH CENTRAL GULF COAST, WILL MOVE LITTLE OR PERHAPS
RETROGRADE TO THE WEST AND SOUTHWEST SATURDAY THROUGH SATURDAY
NIGHT. AN ASSOCIATED BROAD, WEAK LOW-LEVEL BAROCLINIC ZONE MAY
REMAIN QUASI-STATIONARY NEAR/JUST OFFSHORE OF THE CAROLINA COAST
THROUGH NORTHERN FLORIDA, TO A WEAK SURFACE LOW NEAR/OFFSHORE OF THE
SOUTHEASTERN LOUISIANA COAST, BUT THIS REMAINS A BIT UNCERTAIN DUE
TO MODEL SPREAD.
HIGHER MOISTURE CONTENT AIR WILL GENERALLY BE CONFINED TO A CORRIDOR
FOCUSED ABOVE/TO THE COOL SIDE OF THE FRONTAL ZONE, AND WITHIN A
WARM SECTOR PLUME EXTENDING EAST OF THE MID-LEVEL LOW SOUTHWARD
TOWARD THE TROPICAL LATITUDES.
..SOUTHEAST
IN ADDITIONAL TO THE UNCERTAIN DETAILS CONCERNING THE NORTH CENTRAL
GULF FRONTAL LOW AND DOWNSTREAM FRONTAL MOVEMENT, SPREAD EVIDENT IN
MODEL OUTPUT CONCERNING THE SUB-SYNOPTIC DEVELOPMENTS ADDS
UNCERTAINTY TO THE CONVECTIVE FORECAST. HOWEVER, WHILE THE
MID-LEVEL COLD CORE REMAINS WELL UPSTREAM, IT DOES APPEAR THAT MUCH
OF NORTHERN/CENTRAL FLORIDA AND ADJACENT PORTIONS OF THE GULF STATES
WILL REMAIN UNDER THE INFLUENCE OF A BROADLY DIFLUENT, MODEST
SOUTHWESTERLY MID/UPPER FLOW REGIME.
ALTHOUGH HIGHER MOISTURE CONTENT AND MORE WIDESPREAD CONVECTIVE
DEVELOPMENT MAY TEND TO REMAIN FOCUSED WELL OFFSHORE, ACROSS THE
NORTHEASTERN GULF, THE FRONT ZONE AND INLAND ADVANCING SEA-BREEZES
MIGHT PROVIDE FOCUS FOR WIDELY SCATTERED STRONG THUNDERSTORM
DEVELOPMENT DURING THE DAY. AIDED BY MODESTLY STEEP LOWER/MID-LEVEL
LAPSE RATES, THE ENVIRONMENT MAY BECOME CONDUCIVE FOR A FEW OF THESE
STORMS TO POSE A RISK FOR SEVERE HAIL AND WIND. SOME MODEL OUTPUT
SUGGESTS THAT LOW-LEVEL FLOW NORTHEAST OF THE SURFACE LOW MIGHT
CONTRIBUTE TO HODOGRAPHS CONDUCIVE TO SOME RISK FOR A TORNADO,
MAINLY ACROSS AND WEST OF THE FLORIDA BIG BEND VICINITY.
..MONTANA
THERE IS A NOTABLE SIGNAL WITHIN MODEL OUTPUT CONCERNING THE
POTENTIAL FOR THE INITIATION OF THUNDERSTORM ACTIVITY ACROSS THE
HIGHER TERRAIN OF WESTERN MONTANA, AND THE SUBSEQUENT EVOLUTION OF
AN UPSCALE GROWING CLUSTER INTO/ACROSS NORTH CENTRAL MONTANA
SATURDAY AFTERNOON AND EVENING. MOISTURE/INSTABILITY WITHIN
THERMODYNAMIC PROFILES CHARACTERIZED BY THE EVOLUTION OF A DEEP AND
WELL-MIXED BOUNDARY IS FORECAST TO BE WEAK. BUT SHEAR/MOMENTUM
ASSOCIATED WITH 40-50+ KT WEST-SOUTHWESTERLY MID/UPPER FLOW MAY
BECOME CONDUCIVE TO A FEW STORMS INITIALLY POSING A RISK FOR SMALL
TO MARGINALLY SEVERE HAIL, BEFORE STRONG TO SEVERE WIND GUSTS BECOME
THE PRIMARY POTENTIAL HAZARD UNTIL STORMS WEAKEN SATURDAY NIGHT.
..KERR.. 05/09/2025
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