Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 031731
SWODY2
SPC AC 031730

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT FRI JUL 03 2015

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL HIGH
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS FOR MUCH OF THE HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE LOWER MS RIVER
VALLEY/SOUTHEAST STATES...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE GREAT BASIN...

...SUMMARY...
SCATTERED STRONG STORMS WILL POSE A RISK FOR SEVERE WIND GUSTS AND
HAIL ON SATURDAY...THE 4TH OF JULY...MAINLY DURING THE AFTERNOON AND
EVENING HOURS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY...THE
NORTHERN AND CENTRAL HIGH PLAINS...AND THE GREAT BASIN.

...SYNOPSIS...
SPLIT UPPER-LEVEL FLOW WILL PREVAIL OVER THE CONUS ON SATURDAY JULY
4TH. IN THE SOUTHERN STREAM...A MODERATE BELT OF WESTERLIES WILL
ACCOMPANY A SLOW-EASTWARD-MOVING UPPER LOW OVER THE LOWER MS RIVER
VALLEY/SOUTHEAST STATES...WHILE THE UPPER RIDGE ABATES OVER THE
GREAT BASIN. A STRONGER NORTHERN STREAM WILL BE HIGHLIGHTED BY AN
AMPLIFYING UPPER TROUGH OVER THE CANADIAN ROCKIES/PRAIRIES...WHICH
WILL RELATE TO A SOUTHEASTWARD-MOVING FRONT INTO PORTIONS OF
MT/DAKOTAS SATURDAY NIGHT.

...CENTRAL/SOUTHERN HIGH PLAINS...
THE TIMING OF WEAK MID-LEVEL PERTURBATIONS ON THE PERIPHERY OF THE
CENTRAL/SOUTHERN ROCKIES UPPER RIDGE STILL REMAINS UNCLEAR.
HOWEVER...CURRENT THINKING IS THAT AT LEAST ISOLATED/WIDELY
SCATTERED STRONGER THUNDERSTORMS SHOULD DEVELOP SATURDAY
AFTERNOON/EARLY EVENING MAINLY IN VICINITY A NORTH-SOUTH SURFACE
TROUGH. ALTHOUGH LOW/MID-TROPOSPHERIC WINDS WILL GENERALLY BE
WEAK...AMPLE VEERING WITH HEIGHT AND STRONG HIGH-LEVEL NORTHWESTERLY
WINDS WILL SUPPORT SOME SUPERCELLS SATURDAY LATE AFTERNOON/EVENING
IN THE PRESENCE OF MODERATE /2000+ J PER KG/ MLCAPE.

IT IS CONCEIVABLE THAT ONE OR MORE SOUTH-SOUTHEASTWARD-MOVING MCS/S
COULD EVOLVE SATURDAY EVENING WITH AID OF A NOCTURNALLY
STRENGTHENING LOW-LEVEL JET. ADDITIONAL PORTIONS OF THE
REGION...POTENTIALLY INCLUDING MORE OF WESTERN KS AND PARTS OF THE
TX PANHANDLE/WESTERN OK...COULD WARRANT A SLIGHT RISK UPGRADE IN THE
DAY 1 TIME FRAME PENDING A GREATER CONFIDENCE IN STORM
COVERAGE/SUSTENANCE IN AN ENVIRONMENT OTHERWISE RELATIVELY FAVORABLE
FOR ORGANIZED STORM MODES.

...MT/ND...
RELATED TO THE SYNOPSIS-DESCRIBED TROUGH AMPLIFICATION...UPPER
HEIGHT FALLS WILL BEGIN TO SPREAD SOUTH OF THE INTERNATIONAL BORDER
BY SATURDAY NIGHT. A SURFACE TRIPLE POINT WILL BECOME INCREASINGLY
ESTABLISHED ACROSS THE NORTHERN HIGH PLAINS SATURDAY
AFTERNOON/EVENING VIA AN EASTWARD-MOVING FRONTAL WAVE...SHARPENING
PRE-FRONTAL TROUGH...AND SOUTHEASTWARD-MOVING FRONT ACROSS
MT/WESTERN ND. AT LEAST ISOLATED STRONG/SEVERE THUNDERSTORMS COULD
DEVELOP/MOVE SOUTHEASTWARD INTO THE REGION SATURDAY
AFTERNOON/EVENING...WITH SEVERE HAIL/LOCALLY DAMAGING WINDS A
POSSIBILITY. PARTS OF NORTHEAST MT INTO ND COULD WARRANT AN UPGRADE
TO SLIGHT RISK IN THE DAY 1 PERIOD.

...LOWER MS RIVER VALLEY/SOUTHEAST STATES...
WEAK HEIGHT FALLS AND A BELT OF MODERATELY STRONG/SEMI-COOL CYCLONIC
FLOW ALOFT WILL LARGELY COINCIDE WITH AN EFFECTIVE FRONTAL ZONE
REGULATED BY PRIOR CONVECTIVE OUTFLOWS/DIFFERENTIAL HEATING. A
GRADUAL INCREASE/INTENSIFICATION OF EAST-SOUTHEASTWARD-MOVING
THUNDERSTORMS SEEMS PROBABLE BY MIDDAY/EARLY AFTERNOON SATURDAY.
SOME SEMI-ORGANIZED CLUSTERS MAY EVOLVE...WITH LOCALLY DAMAGING
WINDS BEING THE PRIMARY CONCERN SATURDAY AFTERNOON THROUGH
EARLY/MID-EVENING.

...GREAT BASIN...
A BELT OF MODESTLY STRONGER SOUTHERLY MID/HIGH-LEVEL WINDS WILL
OVERSPREAD THE REGION IN CONJUNCTION WITH A WEAKENING UPPER RIDGE. A
DIURNALLY HEATED/WELL-MIXED BOUNDARY LAYER WILL CONTRIBUTE TO THE
DEVELOPMENT/INTENSIFICATION OF THUNDERSTORMS SATURDAY
AFTERNOON/EARLY EVENING MOSTLY ACROSS NV. DOWNBURSTS AND POSSIBLY
SOME HAIL /MOSTLY SUB-SEVERE/ CAN BE EXPECTED WITH THE STRONGER
STORMS.

..GUYER.. 07/03/2015




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