Severe Storm Outlook Narrative (AC)
Issued by NWS

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016
ACUS01 KWNS 270541
SWODY1
SPC AC 270539

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1239 AM CDT WED JUL 27 2016

VALID 271200Z - 281200Z

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS NRN NEW ENGLAND...

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

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE MIDDLE ATLANTIC...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS SERN AZ...

...SUMMARY...
STRONG THUNDERSTORMS MAY IMPACT PARTS OF THE CENTRAL PLAINS...THE
HIGH PLAINS...THE MID ATLANTIC COAST REGION...SOUTHEASTERN ARIZONA
AND NORTHERN MAINE ON WEDNESDAY...WITH SOME RISK FOR SEVERE WEATHER.

...DISCUSSION...

LARGE-SCALE PATTERN WILL CONTINUE TO FAVOR STRONGER FLOW NEAR AND
NORTH OF THE INTERNATIONAL BORDER WEDNESDAY AS PROMINENT UPPER LOW
PROGRESSES INTO QC.  SRN INFLUENCE OF THIS TROUGH WILL AFFECT
CONVECTION ACROSS NRN NEW ENGLAND WHILE DEEPENING NWLY FLOW ACROSS
THE HIGH PLAINS ENHANCES THE POTENTIAL FOR A FEW ORGANIZED STORMS
OVER THIS REGION.  ELSEWHERE...A FEW STRONG STORMS MAY DEVELOP IN
THE MIDDLE ATLANTIC AND DESERT SW DURING THE HEAT OF THE DAY.

1.  NEW ENGLAND.  SEASONALLY STRONG MID-LEVEL FLOW WILL EXTEND
ACROSS QC INTO NRN NEW ENGLAND...WELL AHEAD OF SFC FRONT THAT SHOULD
REMAIN NORTH OF THE BORDER THROUGH PEAK HEATING.  LATEST SHORT-RANGE
GUIDANCE SUGGESTS ISOLATED TSTMS WILL EVOLVE ALONG THE BOUNDARY
ACROSS QC AND THIS ACTIVITY COULD SPREAD INTO NRN ME BY EARLY
EVENING.  GUSTY WINDS AND MARGINALLY SEVERE HAIL ARE POSSIBLE.

2.  PLAINS.  WITH UPPER RIDGE EXPECTED TO HOLD OVER THE GREAT
BASIN...NWLY FLOW SHOULD PERSIST ACROSS THE HIGH PLAINS DURING THE
DAY1 PERIOD.  WEAK SHORT-WAVE RIDGING IS EXPECTED ACROSS WY DURING
THE DAY...PRIMARILY IN THE WAKE OF AN EARLY-DAY MCS THAT IS
SPREADING SEWD ACROSS NEBRASKA.  LEADING EDGE OF THIS ACTIVITY
SHOULD BE NEAR THE KS BORDER BY DAYBREAK AND FOR THIS REASON HAVE
ADJUSTED 5 PERCENT SEVERE PROBS SOUTH A BIT TO ACCOUNT FOR A MORE
SRN EXTENT TO OUTFLOW/SFC FRONT.  DIURNAL HEATING WILL BE THE
PRIMARY FACTOR IN ISOLATED THUNDERSTORM DEVELOPMENT DURING THE DAY
FROM SERN MT INTO ERN CO.  IN THE ABSENCE OF MEANINGFUL LARGE-SCALE
ASCENT...TOPOGRAPHY WILL INFLUENCE INITIATION.  LARGE HAIL/DAMAGING
WINDS MAY BE NOTED WITH THE STRONGEST STORMS.

3.  MIDDLE ATLANTIC.  STRONG SFC HEATING WILL ONCE AGAIN CONTRIBUTE
TO ROBUST TSTM ACTIVITY ACROSS PORTIONS OF THE MIDDLE ATLANTIC.
WITH WLY FLOW ON THE ORDER OF 20KT THIS ACTIVITY COULD EXHIBIT
LOOSELY ORGANIZED MULTI-CELL UPDRAFTS...THOUGH STORM MERGERS AND
HIGH PW AIR MASS WOULD PRIMARILY BE RESPONSIBLE FOR GENERATING
LOCALLY DAMAGING WIND THREAT.

4.  AZ.  NELY 500MB FLOW AROUND 20KT WILL BE NOTED ACROSS NM INTO
SERN AZ AS UPPER RIDGE REMAINS CENTERED OVER THE GREAT BASIN.  GUSTY
WINDS COULD CERTAINLY BE NOTED WITH CONVECTION AS IT PROPAGATES OFF
THE HIGHER TERRAIN TOWARD LOWER ELEVATIONS.

..DARROW/GLEASON.. 07/27/2016

$$



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