Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 290421
SWODY2
SPC AC 290420

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1120 PM CDT THU JUL 28 2016

VALID 301200Z - 311200Z

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

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE
MID-ATLANTIC...

...SUMMARY...
ISOLATED STRONG STORMS ARE POSSIBLE ACROSS PARTS OF THE CENTRAL HIGH
PLAINS AND MID-ATLANTIC REGION SATURDAY AFTERNOON AND EVENING.

...HIGH PLAINS...

ELONGATED UPPER RIDGE IS EXPECTED TO HOLD ACROSS THE SWRN U.S.
THROUGH THE DAY2 PERIOD WITH NEUTRAL TO WEAK 12HR MID-LEVEL HEIGHT
RISES EXPECTED ACROSS THE HIGH PLAINS.  LATE DAY1/FRIDAY CONVECTION
ACROSS THE PLAINS WILL LIKELY IMPACT THE POSITION OF SFC BOUNDARY
THAT SHOULD INFLUENCE TSTM DEVELOPMENT SATURDAY.  LATEST MODEL
GUIDANCE SUGGESTS WIND SHIFT WILL BE SHUNTED TO NEAR THE KS/OK
BORDER WHERE IT SHOULD REMAIN MOST OF THE PERIOD.  ALONG THE WRN
FRINGE OF THE MODIFIED CNTRL PLAINS AIR MASS SELY LOW-LEVEL FLOW
SHOULD TRANSPORT MOISTURE/INSTABILITY INTO THE HIGHER TERRAIN AND
ISOLATED THUNDERSTORMS SHOULD DEVELOP DURING THE HEAT OF THE DAY.
WHILE MODELS DO NOT SUGGEST ANY MEANINGFUL MID-LEVEL DISTURBANCE
WILL AID THIS ACTIVITY...SEASONALLY STRONG NWLY 500MB FLOW WOULD
PROVE SUPPORTIVE OF ORGANIZED UPDRAFTS...POTENTIALLY SUPERCELLULAR
IN NATURE.  HAVE EXPANDED THE 5 PERCENT SEVERE PROBS SOUTH INTO NWRN
KS TO ACCOUNT FOR BLACK HILLS CONVECTION OR TSTMS THAT DEVELOP OVER
THE NEBRASKA PANHANDLE TO ADVECT INTO THIS REGION.  HAIL/WIND ARE
THE PRIMARY THREATS WITH THIS ACTIVITY.

...MID-ATLANTIC...

BROAD MID-LEVEL TROUGH WILL BE NOTED ACROSS THE OH VALLEY SATURDAY
WITH A BELT OF STRONGER 500MB FLOW...ON THE ORDER OF 30KT...EXPECTED
TO EXTEND ACROSS KS INTO THE DELMARVA THROUGH LATE AFTERNOON.
FORECAST MID-LEVEL LAPSE RATES ALONG THIS CORRIDOR ARE QUITE WEAK
WITH VALUES NEAR PSEUDO-ADIABATIC.  BOUNDARY-LAYER HEATING WILL BE
MAXIMIZED ACROSS THE OH VALLEY...EXTENDING INTO WRN VA WHERE
SYNOPTIC FRONT WILL LIKELY BE DRAPED NW-SE ACROSS THE STATE.  STORMS
THAT FORM NEAR THE BOUNDARY SHOULD HAVE SOMEWHAT ENHANCED
SHEAR...THOUGH BUOYANCY IS NOT EXPECTED TO BE THAT GREAT.  HAVE
MAINTAINED MRGL ACROSS THIS REGION FOR POSSIBLE GUSTY WINDS WITH THE
MORE ROBUST CONVECTION.

...AZ...

WITH UPPER RIDGING EXPECTED TO MOVE LITTLE OVER THE NEXT 48HR...DEEP
ESELY FLOW ALONG THE SRN INTERNATIONAL BORDER WILL MAINTAIN 1.5+
INCH PW ACROSS SRN AZ.  IF DAY1 CONVECTIVE DEBRIS DOES NOT INTERFERE
WITH DIABATIC HEATING...STRONG THUNDERSTORMS MAY DEVELOP OVER THE
HIGH TERRAIN AND DRIFT ACROSS THE LOWER DESERTS.  STRONG DOWNBURSTS
DUE TO WATER LOADING COULD BE NOTED.  TOO MUCH UNCERTAINTY IN DAY1
CONVECTIVE PROCESSES CURRENTLY EXISTS TO ADD MRGL AT THIS TIME.

..DARROW.. 07/29/2016

$$



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