Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 050723
SWODY3
SPC AC 050722

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0222 AM CDT SUN JUL 05 2015

VALID 071200Z - 081200Z

...THERE IS A MRGL RISK OF SVR TSTMS ...MAINLY TUESDAY AFTERNOON AND
EVENING...ACROSS PARTS OF THE LOWER GREAT LAKES REGION...AND THE
OHIO VALLEY INTO PORTIONS OF THE SOUTH CENTRAL PLAINS...

...SUMMARY...
WIDELY SCATTERED STRONG TO SEVERE STORM DEVELOPMENT IS POSSIBLE
TUESDAY IN CORRIDOR FROM THE LOWER GREAT LAKES REGION SOUTHWESTWARD
THROUGH THE LOWER OHIO VALLEY INTO PORTIONS OF THE SOUTH CENTRAL
PLAINS.

...SYNOPSIS...
MID-LATITUDE WESTERLIES APPEAR LIKELY TO REMAIN BROADLY CYCLONIC
EAST OF THE CANADIAN ROCKIES THROUGH MUCH OF THE REMAINDER OF
CANADA...AND ADJACENT NORTHERN U.S. PLAINS THROUGH UPPER GREAT LAKES
REGION...DURING THIS PERIOD.  MODELS INDICATE AT LEAST A COUPLE OF
SIGNIFICANT PERTURBATIONS EMBEDDED WITHIN THIS REGIME...INCLUDING
ONE FORECAST TO GRADUALLY PIVOT TO THE NORTHEAST OF THE UPPER GREAT
LAKES REGION.  IN LOWER LATITUDES...THE EASTERN PERIPHERY OF A BROAD
CLOSED LOW EMERGING FROM AN IMPULSE OF SUBTROPICAL EASTERN PACIFIC
ORIGINS MAY GRADUALLY SPREAD INLAND ACROSS CALIFORNIA.
DOWNSTREAM...A NARROW BELT OF MODEST WEST SOUTHWESTERLY MID-LEVEL
FLOW MAY DEVELOP ON THE NORTHERN PERIPHERY OF SUPPRESSED SUBTROPICAL
RIDGING /CENTERED OFF THE SOUTH ATLANTIC COAST/...FROM THE SOUTHERN
PLAINS INTO THE CENTRAL APPALACHIANS.

...LOWER GREAT LAKES/OHIO VALLEY INTO THE SOUTH CENTRAL PLAINS...
A COLD FRONT ASSOCIATED WITH THE MID-LATITUDE WESTERLIES...PERHAPS
PRECEDED/MASKED BY CONSIDERABLE CONVECTIVE OUTFLOW...PROBABLY WILL
SLOW OR STALL ACROSS PORTIONS OF THE SOUTH CENTRAL PLAINS INTO LOWER
OHIO VALLEY...WHILE CONTINUING TO ADVANCE SOUTHEASTWARD ACROSS THE
LOWER GREAT LAKES REGION AND UPPER OHIO VALLEY BY LATE TUESDAY
NIGHT.  THIS IS EXPECTED TO REMAIN GENERALLY TO THE EAST AND SOUTH
OF THE STRONGER MID-LATITUDE WESTERLIES...AND BENEATH A RELATIVELY
WARM MID/UPPER TROPOSPHERIC ENVIRONMENT CHARACTERIZED BY GENERALLY
WEAK LAPSE RATES.  EVEN WITHIN A SEASONABLY MOIST PRE-FRONTAL
CORRIDOR...MIXED LAYER CAPE MAY NOT EXCEED 1000-2000 J/KG.  DESPITE
THESE LIMITATIONS...DESTABILIZATION AND FORCING IS EXPECTED TO BE
SUFFICIENT TO SUPPORT RENEWED THUNDERSTORM ACTIVITY ALONG/AHEAD OF
THE FRONT TUESDAY AFTERNOON AND EVENING.  IT IS POSSIBLE THAT THIS
ACTIVITY COULD BE ENHANCED BY A BELT OF LOWER/MID TROPOSPHERIC FLOW
ON THE ORDER OF 30 KT OR SO...WITH HEAVY PRECIPITATION LOADING AND
DOWNWARD MIXING OF THIS MOMENTUM CONTRIBUTING TO AT LEAST SOME RISK
FOR POTENTIALLY DAMAGING WIND GUSTS.

..KERR.. 07/05/2015



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